diff --git a/sdk/core/azure-core/CHANGELOG.md b/sdk/core/azure-core/CHANGELOG.md
index 0f01d4192b11..a10d98e83e6a 100644
--- a/sdk/core/azure-core/CHANGELOG.md
+++ b/sdk/core/azure-core/CHANGELOG.md
@@ -9,6 +9,7 @@
 ### Bug Fixes
 
 - Retry policies don't sleep after operations time out
+- The `from_dict` methhod in the `CloudEvent` can now convert a datetime string to datetime object when microsecond exceeds the python limitation
 
 
 ## 1.14.0 (2021-05-13)
diff --git a/sdk/core/azure-core/azure/core/_utils.py b/sdk/core/azure-core/azure/core/_utils.py
index aae272ed729b..5f3133e02955 100644
--- a/sdk/core/azure-core/azure/core/_utils.py
+++ b/sdk/core/azure-core/azure/core/_utils.py
@@ -53,6 +53,17 @@ def _convert_to_isoformat(date_time):
         sign, offset = date_time[-6], date_time[-5:]
         delta = int(sign + offset[:1]) * 60 + int(sign + offset[-2:])
 
+    check_decimal = timestamp.split('.')
+    if len(check_decimal) > 1:
+        decimal_str = ""
+        for digit in check_decimal[1]:
+            if digit.isdigit():
+                decimal_str += digit
+            else:
+                break
+        if len(decimal_str) > 6:
+            timestamp = timestamp.replace(decimal_str, decimal_str[0:6])
+
     if delta == 0:
         tzinfo = TZ_UTC
     else:
diff --git a/sdk/core/azure-core/tests/test_messaging_cloud_event.py b/sdk/core/azure-core/tests/test_messaging_cloud_event.py
index c0a88b845488..9dd8b80a7fbc 100644
--- a/sdk/core/azure-core/tests/test_messaging_cloud_event.py
+++ b/sdk/core/azure-core/tests/test_messaging_cloud_event.py
@@ -98,7 +98,7 @@ def test_cloud_storage_dict():
             "storage_diagnostics":{"batchId":"b68529f3-68cd-4744-baa4-3c0498ec19f0"}
         },
         "type":"Microsoft.Storage.BlobCreated",
-        "time":"2021-02-18T20:18:10.53986Z",
+        "time":"2021-02-18T20:18:10.581147898Z",
         "specversion":"1.0"
     }
 
@@ -120,6 +120,7 @@ def test_cloud_storage_dict():
     assert event.time.month == 2
     assert event.time.day == 18
     assert event.time.hour == 20
+    assert event.time.microsecond == 581147
     assert event.__class__ == CloudEvent
     assert "id" in cloud_storage_dict
     assert "data" in cloud_storage_dict
@@ -131,7 +132,7 @@ def test_cloud_custom_dict_with_extensions():
         "source":"https://egtest.dev/cloudcustomevent",
         "data":{"team": "event grid squad"},
         "type":"Azure.Sdk.Sample",
-        "time":"2021-02-18T20:18:10.53986+00:00",
+        "time":"2021-02-18T20:18:10.539861122+00:00",
         "specversion":"1.0",
         "ext1": "example",
         "ext2": "example2"
@@ -142,6 +143,7 @@ def test_cloud_custom_dict_with_extensions():
     assert event.time.month == 2
     assert event.time.day == 18
     assert event.time.hour == 20
+    assert event.time.microsecond == 539861
     assert event.extensions == {"ext1": "example", "ext2": "example2"}
 
 def test_cloud_custom_dict_blank_data():