diff --git a/backend/apps/pisadmin/miscprocurement/tasks.py b/backend/apps/pisadmin/miscprocurement/tasks.py
new file mode 100644
index 0000000..db44d93
--- /dev/null
+++ b/backend/apps/pisadmin/miscprocurement/tasks.py
@@ -0,0 +1,179 @@
+# -*- coding: utf-8 -*-
+"""
+Celery 定时任务：报价截止时间到期邮件通知采购。
+"""
+import logging
+from typing import Dict, Any, List
+
+from django.utils import timezone
+
+from application.celery import app
+from apps.pissupplier.models import QuotationMaster
+from apps.pisadmin.miscprocurement.models import Inquiry
+
+logger = logging.getLogger(__name__)
+
+
+def _is_in_cooldown(inquiry_no: str, cooldown_hours: int = 24) -> bool:
+    """
+    检查该询价单是否在冷却期内（24h内已成功发送过）。
+    复用 email_utils 的冷却判断逻辑。
+    """
+    from apps.pisadmin.basicinfo.views.email_utils import should_send_quote_timeout_reminder
+    return not should_send_quote_timeout_reminder(inquiry_no, cooldown_hours=cooldown_hours)
+
+
+def _get_purchaser_emails(inquiry_no: str) -> List[str]:
+    """根据询价单号获取采购负责人邮箱列表。"""
+    from apps.pisadmin.basicinfo.views.email_utils import resolve_inquiry_purchaser_emails
+    inquiry = Inquiry.objects.filter(inquiry_no=inquiry_no).first()
+    if not inquiry:
+        return []
+    return resolve_inquiry_purchaser_emails(inquiry)
+
+
+def _build_expired_supplier_list(inquiry_no: str) -> List[Dict[str, Any]]:
+    """
+    构建某询价单下所有已到期未报价供应商列表。
+    """
+    now = timezone.now()
+    rows = QuotationMaster.objects.filter(
+        inquiry_no=inquiry_no,
+        status__in=(1, 2),  # 1=待报价, 2=报价中
+        quote_deadline__lt=now,
+    ).values("supplier_name", "contact_person", "contact_phone", "quote_deadline", "status")
+
+    result = []
+    for row in rows:
+        deadline_local = row["quote_deadline"]
+        if deadline_local and timezone.is_aware(deadline_local):
+            from django.utils.timezone import localtime
+            deadline_display = localtime(deadline_local).strftime("%Y-%m-%d %H:%M")
+        else:
+            deadline_display = str(deadline_local or "—")
+
+        result.append({
+            "supplier_name": row["supplier_name"] or "—",
+            "contact_person": row["contact_person"] or None,
+            "quote_deadline": deadline_display,
+            "status": row["status"],
+        })
+    return result
+
+
+def _send_deadline_expired_email(inquiry: Inquiry, expired_suppliers: List[Dict[str, Any]]) -> bool:
+    """
+    渲染并发送单封报价截止到期邮件（一个询价单合并所有供应商）。
+    复用 email_utils 的 send_email_notice 底层。
+    """
+    from apps.pisadmin.basicinfo.views.email_template import (
+        TEMPLATE_QUOTE_DEADLINE_EXPIRED,
+        build_context_quote_deadline_expired,
+        render_email,
+    )
+    from apps.pisadmin.basicinfo.views.email_utils import send_email_notice
+    from apps.pisadmin.basicinfo.models import EmailNotice
+
+    to_list = _get_purchaser_emails(inquiry.inquiry_no)
+    if not to_list:
+        logger.warning("报价截止提醒无法找到采购负责人邮箱，inquiry_no=%s", inquiry.inquiry_no)
+        return False
+
+    ctx = build_context_quote_deadline_expired(inquiry, expired_suppliers)
+    subject, body = render_email(TEMPLATE_QUOTE_DEADLINE_EXPIRED, ctx)
+
+    notice = EmailNotice.objects.create(
+        subject=subject,
+        body=body,
+        to_emails=to_list,
+        cc_emails=[],
+        bcc_emails=[],
+        attachments=[],
+        biz_type="inquiry_quote_timeout",  # 复用现有 biz_type 用于冷却期判断
+        biz_id=inquiry.inquiry_no,
+        status="pending",
+        payload={
+            "template_key": TEMPLATE_QUOTE_DEADLINE_EXPIRED,
+            "is_html": True,
+            "inquiry_no": ctx.get("inquiry_no"),
+            "supplier_count": ctx.get("supplier_count"),
+        },
+    )
+    notice.status = "sending"
+    notice.save(update_fields=["status", "update_datetime"])
+
+    success, detail = send_email_notice(notice)
+    notice.response = detail or {}
+    if success:
+        notice.status = "success"
+        notice.sent_at = timezone.now()
+        notice.last_error = None
+    else:
+        notice.status = "failed"
+        notice.last_error = detail.get("error") if isinstance(detail, dict) else str(detail)
+
+    notice.save(update_fields=["status", "sent_at", "response", "last_error", "update_datetime"])
+    return success
+
+
+@app.task(bind=True, max_retries=3, default_retry_delay=180)
+def check_quote_deadline_expired(self) -> Dict[str, int]:
+    """
+    Celery Beat 定时任务：轮询报价截止时间已到期的报价单，
+    按询价单合并发送邮件通知采购负责人，每天最多一次。
+
+    查询条件：status ∈ {1, 2}（待报价/报价中）且 quote_deadline < now
+
+    Returns: {"checked": N, "sent": M, "skipped": K, "errors": E}
+    """
+    now = timezone.now()
+
+    # 1. 找出所有已到期但未报价的报价单
+    expired_qs = QuotationMaster.objects.filter(
+        status__in=(1, 2),
+        quote_deadline__isnull=False,
+        quote_deadline__lt=now,
+    ).values_list("inquiry_no", flat=True).distinct()
+
+    # 2. 按 inquiry_no 分组
+    inquiry_nos = list(expired_qs)
+
+    checked = len(inquiry_nos)
+    sent = 0
+    skipped = 0
+    errors = 0
+
+    for inq_no in inquiry_nos:
+        # 3. 检查24h冷却期
+        if _is_in_cooldown(inq_no, cooldown_hours=24):
+            skipped += 1
+            continue
+
+        # 4. 获取 Inquiry 对象
+        inquiry = Inquiry.objects.filter(inquiry_no=inq_no).first()
+        if not inquiry:
+            logger.warning("报价截止提醒未找到询价单，inquiry_no=%s", inq_no)
+            skipped += 1
+            continue
+
+        # 5. 构建到期供应商列表
+        expired_suppliers = _build_expired_supplier_list(inq_no)
+        if not expired_suppliers:
+            skipped += 1
+            continue
+
+        # 6. 发送邮件
+        try:
+            if _send_deadline_expired_email(inquiry, expired_suppliers):
+                sent += 1
+            else:
+                errors += 1
+        except Exception:
+            logger.exception("报价截止提醒邮件发送异常，inquiry_no=%s", inq_no)
+            errors += 1
+
+    logger.info(
+        "报价截止提醒任务完成: checked=%d, sent=%d, skipped=%d, errors=%d",
+        checked, sent, skipped, errors,
+    )
+    return {"checked": checked, "sent": sent, "skipped": skipped, "errors": errors}