diff --git a/aodh/evaluator/event.py b/aodh/evaluator/event.py
index c38f201c1..2c800dba6 100644
--- a/aodh/evaluator/event.py
+++ b/aodh/evaluator/event.py
@@ -17,6 +17,7 @@ import operator
 
 from oslo_config import cfg
 from oslo_log import log
+from oslo_serialization import jsonutils
 from oslo_utils import fnmatch
 from oslo_utils import timeutils
 import six
@@ -248,9 +249,12 @@ class EventAlarmEvaluator(evaluator.Evaluator):
         """Update alarm state and fire alarm via alarm notifier."""
 
         state = evaluator.ALARM
-        reason = (_('Event (message_id=%(message)s) hit the query of alarm '
-                    '(id=%(alarm)s)') %
-                  {'message': event.id, 'alarm': alarm.id})
+        reason = (_('Event <id=%(id)s,event_type=%(event_type)s> hits the '
+                    'query <query=%(alarm_query)s>.') %
+                  {'id': event.id,
+                   'event_type': event.get_value('event_type'),
+                   'alarm_query': jsonutils.dumps(alarm.obj.rule['query'],
+                                                  sort_keys=True)})
         reason_data = {'type': 'event', 'event': event.obj}
         always_record = alarm.obj.repeat_actions
         self._refresh(alarm.obj, state, reason, reason_data, always_record)
diff --git a/aodh/tests/unit/evaluator/test_event.py b/aodh/tests/unit/evaluator/test_event.py
index 5672804d2..106d39893 100644
--- a/aodh/tests/unit/evaluator/test_event.py
+++ b/aodh/tests/unit/evaluator/test_event.py
@@ -19,6 +19,7 @@ import six
 import uuid
 
 import mock
+from oslo_serialization import jsonutils
 from oslo_utils import timeutils
 
 from aodh import evaluator
@@ -122,9 +123,12 @@ class TestEventAlarmEvaluate(base.TestEvaluatorBase):
                 alarm = n['alarm']
                 event = n['event']
                 previous = n.get('previous', evaluator.UNKNOWN)
-                reason = ('Event (message_id=%(e)s) hit the query of alarm '
-                          '(id=%(a)s)' %
-                          {'e': event['message_id'], 'a': alarm.alarm_id})
+                reason = ('Event <id=%(e)s,event_type=%(type)s> hits the '
+                          'query <query=%(query)s>.') % {
+                    'e': event['message_id'],
+                    'type': event['event_type'],
+                    'query': jsonutils.dumps(alarm.rule['query'],
+                                             sort_keys=True)}
                 data = {'type': 'event', 'event': event}
                 expected = dict(alarm_id=alarm.alarm_id,
                                 state=evaluator.ALARM,