diff --git a/crates/erp-health/src/service/alert_engine.rs b/crates/erp-health/src/service/alert_engine.rs
index 5375f6b..d5918ad 100644
--- a/crates/erp-health/src/service/alert_engine.rs
+++ b/crates/erp-health/src/service/alert_engine.rs
@@ -2,6 +2,7 @@ use chrono::Utc;
 use sea_orm::entity::prelude::*;
 use sea_orm::{ActiveValue::Set, QueryOrder, QuerySelect};
 use serde_json::json;
+use std::collections::HashSet;
 use uuid::Uuid;
 
 use crate::entity::{alert_rules, alerts, vital_signs_hourly};
@@ -23,10 +24,37 @@ pub async fn evaluate_rules(
         .all(&state.db)
         .await?;
 
+    if rules.is_empty() {
+        return Ok(Vec::new());
+    }
+
+    // 批量查询 cooldown 期间的 alerts
+    let max_cooldown: i64 = rules.iter().map(|r| r.cooldown_minutes as i64).max().unwrap_or(60);
+    let cooldown_start = Utc::now() - chrono::Duration::minutes(max_cooldown);
+    let recent_alerts = alerts::Entity::find()
+        .filter(alerts::Column::TenantId.eq(tenant_id))
+        .filter(alerts::Column::PatientId.eq(patient_id))
+        .filter(alerts::Column::CreatedAt.gt(cooldown_start))
+        .filter(alerts::Column::DeletedAt.is_null())
+        .all(&state.db)
+        .await?;
+    let cooldown_set: HashSet<Uuid> = recent_alerts.iter().map(|a| a.rule_id).collect();
+
+    // 批量查询最近的 hourly 记录（最多取最近 168 小时用于 trend 判断）
+    let hourly_records = vital_signs_hourly::Entity::find()
+        .filter(vital_signs_hourly::Column::TenantId.eq(tenant_id))
+        .filter(vital_signs_hourly::Column::PatientId.eq(patient_id))
+        .filter(vital_signs_hourly::Column::DeviceType.eq(device_type))
+        .filter(vital_signs_hourly::Column::HourStart.gt(Utc::now() - chrono::Duration::hours(168)))
+        .order_by_desc(vital_signs_hourly::Column::HourStart)
+        .all(&state.db)
+        .await?;
+
     let mut triggered_alerts = Vec::new();
 
     for rule in rules {
-        if is_in_cooldown(&state.db, tenant_id, patient_id, rule.id, rule.cooldown_minutes).await? {
+        // 检查 cooldown（使用预先查询的集合）
+        if cooldown_set.contains(&rule.id) {
             continue;
         }
 
@@ -34,15 +62,9 @@ pub async fn evaluate_rules(
         let condition_type = rule.condition_type.as_str();
 
         let is_triggered = match condition_type {
-            "single_threshold" => evaluate_single_threshold(
-                &state.db, tenant_id, patient_id, device_type, params
-            ).await?,
-            "consecutive" => evaluate_consecutive(
-                &state.db, tenant_id, patient_id, device_type, params
-            ).await?,
-            "trend" => evaluate_trend(
-                &state.db, tenant_id, patient_id, device_type, params
-            ).await?,
+            "single_threshold" => evaluate_single_threshold_in_memory(&hourly_records, params),
+            "consecutive" => evaluate_consecutive_in_memory(&hourly_records, params),
+            "trend" => evaluate_trend_in_memory(&hourly_records, params),
             _ => false,
         };
 
@@ -57,90 +79,49 @@ pub async fn evaluate_rules(
     Ok(triggered_alerts)
 }
 
-async fn is_in_cooldown(
-    db: &DatabaseConnection,
-    tenant_id: Uuid,
-    patient_id: Uuid,
-    rule_id: Uuid,
-    cooldown_minutes: i32,
-) -> HealthResult<bool> {
-    let cooldown_start = Utc::now() - chrono::Duration::minutes(cooldown_minutes as i64);
-    let recent = alerts::Entity::find()
-        .filter(alerts::Column::TenantId.eq(tenant_id))
-        .filter(alerts::Column::PatientId.eq(patient_id))
-        .filter(alerts::Column::RuleId.eq(rule_id))
-        .filter(alerts::Column::CreatedAt.gt(cooldown_start))
-        .filter(alerts::Column::DeletedAt.is_null())
-        .one(db)
-        .await?;
-    Ok(recent.is_some())
-}
-
-async fn evaluate_single_threshold(
-    db: &DatabaseConnection,
-    tenant_id: Uuid,
-    patient_id: Uuid,
-    device_type: &str,
+fn evaluate_single_threshold_in_memory(
+    records: &[vital_signs_hourly::Model],
     params: &serde_json::Value,
-) -> HealthResult<bool> {
+) -> bool {
     let direction = params["direction"].as_str().unwrap_or("above");
     let threshold = params["value"].as_f64().unwrap_or(f64::MAX);
 
-    let latest = vital_signs_hourly::Entity::find()
-        .filter(vital_signs_hourly::Column::TenantId.eq(tenant_id))
-        .filter(vital_signs_hourly::Column::PatientId.eq(patient_id))
-        .filter(vital_signs_hourly::Column::DeviceType.eq(device_type))
-        .order_by_desc(vital_signs_hourly::Column::HourStart)
-        .one(db)
-        .await?;
-
-    match latest {
+    // records 已按 HourStart DESC 排序，第一条即最新
+    match records.first() {
         Some(record) => {
             let val = record.avg_val;
-            Ok(match direction {
+            match direction {
                 "above" => val > threshold,
                 "below" => val < threshold,
                 _ => false,
-            })
+            }
         }
-        None => Ok(false),
+        None => false,
     }
 }
 
-async fn evaluate_consecutive(
-    db: &DatabaseConnection,
-    tenant_id: Uuid,
-    patient_id: Uuid,
-    device_type: &str,
+fn evaluate_consecutive_in_memory(
+    records: &[vital_signs_hourly::Model],
     params: &serde_json::Value,
-) -> HealthResult<bool> {
-    let count = params["count"].as_u64().unwrap_or(3) as u64;
+) -> bool {
+    let count = params["count"].as_u64().unwrap_or(3) as usize;
     let direction = params["direction"].as_str().unwrap_or("above");
     let threshold = params["value"].as_f64().unwrap_or(f64::MAX);
     let window_hours = params["window_hours"].as_i64();
 
-    use sea_orm::QueryOrder;
-    let mut query = vital_signs_hourly::Entity::find()
-        .filter(vital_signs_hourly::Column::TenantId.eq(tenant_id))
-        .filter(vital_signs_hourly::Column::PatientId.eq(patient_id))
-        .filter(vital_signs_hourly::Column::DeviceType.eq(device_type))
-        .order_by_desc(vital_signs_hourly::Column::HourStart);
+    // records 已按 HourStart DESC 排序
+    let cutoff = window_hours.map(|h| Utc::now() - chrono::Duration::hours(h));
+    let recent: Vec<_> = records
+        .iter()
+        .take_while(|r| cutoff.map_or(true, |c| r.hour_start > c))
+        .take(count)
+        .collect();
 
-    if let Some(hours) = window_hours {
-        let since = Utc::now() - chrono::Duration::hours(hours);
-        query = query.filter(vital_signs_hourly::Column::HourStart.gt(since));
+    if recent.len() < count {
+        return false;
     }
 
-    let records: Vec<_> = query
-        .limit(count)
-        .all(db)
-        .await?;
-
-    if records.len() < count as usize {
-        return Ok(false);
-    }
-
-    let all_exceed = records.iter().all(|r| {
+    let all_exceed = recent.iter().all(|r| {
         match direction {
             "above" => r.avg_val > threshold,
             "below" => r.avg_val < threshold,
@@ -148,45 +129,39 @@ async fn evaluate_consecutive(
         }
     });
 
-    Ok(all_exceed)
+    all_exceed
 }
 
-async fn evaluate_trend(
-    db: &DatabaseConnection,
-    tenant_id: Uuid,
-    patient_id: Uuid,
-    device_type: &str,
+fn evaluate_trend_in_memory(
+    records: &[vital_signs_hourly::Model],
     params: &serde_json::Value,
-) -> HealthResult<bool> {
+) -> bool {
     let window_hours = params["window_hours"].as_i64().unwrap_or(168);
     let delta_threshold = params["delta"].as_f64().unwrap_or(20.0);
     let direction = params["direction"].as_str().unwrap_or("up");
 
     let since = Utc::now() - chrono::Duration::hours(window_hours);
 
-    use sea_orm::QueryOrder;
-    let records: Vec<_> = vital_signs_hourly::Entity::find()
-        .filter(vital_signs_hourly::Column::TenantId.eq(tenant_id))
-        .filter(vital_signs_hourly::Column::PatientId.eq(patient_id))
-        .filter(vital_signs_hourly::Column::DeviceType.eq(device_type))
-        .filter(vital_signs_hourly::Column::HourStart.gt(since))
-        .order_by_asc(vital_signs_hourly::Column::HourStart)
-        .all(db)
-        .await?;
+    // records 已按 HourStart DESC 排序，需要按时间正序取首尾
+    let mut in_window: Vec<_> = records
+        .iter()
+        .filter(|r| r.hour_start > since)
+        .collect();
+    in_window.sort_by_key(|r| r.hour_start);
 
-    if records.len() < 2 {
-        return Ok(false);
+    if in_window.len() < 2 {
+        return false;
     }
 
-    let first = records.first().unwrap().avg_val;
-    let last = records.last().unwrap().avg_val;
+    let first = in_window.first().unwrap().avg_val;
+    let last = in_window.last().unwrap().avg_val;
     let actual_delta = last - first;
 
-    Ok(match direction {
+    match direction {
         "up" => actual_delta > delta_threshold,
         "down" => actual_delta < -delta_threshold,
         _ => false,
-    })
+    }
 }
 
 async fn create_alert_and_notify(