diff --git a/paddlehub/compat/task/base_task.py b/paddlehub/compat/task/base_task.py
index 1740a364d9297b6439dcad4cba1b49d844769349..719f6f9cd9bd2f765ed36ec934b0c6cd687ece09 100644
--- a/paddlehub/compat/task/base_task.py
+++ b/paddlehub/compat/task/base_task.py
@@ -124,7 +124,7 @@ class BaseTask(object):
 
     def enter_phase(self, phase: str):
         if phase not in ['train', 'val', 'dev', 'test', 'predict', 'inference']:
-            raise RuntimeError()
+            raise RuntimeError('Unknown phase {}.'.format(phase))
         if phase in ['val', 'dev']:
             phase = 'dev'
         elif phase in ['predict', 'inference']:
@@ -289,7 +289,7 @@ class BaseTask(object):
     @property
     def loss(self) -> paddle.static.Variable:
         if self.is_predict_phase:
-            raise RuntimeError()
+            raise RuntimeError('Loss cannot be obtained in the prediction phase.')
 
         if not self.env.is_inititalized:
             self._build_env()
@@ -298,7 +298,7 @@ class BaseTask(object):
     @property
     def labels(self) -> List[paddle.static.Variable]:
         if self.is_predict_phase:
-            raise RuntimeError()
+            raise RuntimeError('Labels cannot be obtained in the prediction phase.')
 
         if not self.env.is_inititalized:
             self._build_env()
@@ -313,7 +313,7 @@ class BaseTask(object):
     @property
     def metrics(self) -> List[str]:
         if self.is_predict_phase:
-            raise RuntimeError()
+            raise RuntimeError('Metrics cannot be obtained in the prediction phase.')
 
         if not self.env.is_inititalized:
             self._build_env()
diff --git a/paddlehub/finetune/trainer.py b/paddlehub/finetune/trainer.py
index 3399f1b82477eacb67f21366f9beb2c82bdef992..aacb9bc38e2402ce26ed203ba009daa09d2909cd 100644
--- a/paddlehub/finetune/trainer.py
+++ b/paddlehub/finetune/trainer.py
@@ -314,11 +314,12 @@ class Trainer(object):
 
         # process result
         if not isinstance(result, dict):
-            raise RuntimeError()
+            raise RuntimeError('The return value of `trainning_step` in {} is not a dict'.format(self.model.__class__))
 
         loss = result.get('loss', None)
         if not loss:
-            raise RuntimeError()
+            raise RuntimeError('Cannot find loss attribute in the return value of `trainning_step` of {}'.format(
+                self.model.__class__))
 
         metrics = result.get('metrics', {})
 
diff --git a/paddlehub/server/server.py b/paddlehub/server/server.py
index c07ac1c8cbced117b59f248962cc04431e749dd8..ee228d681a67b824120ea09a3bf0d9d3ddbdcda6 100644
--- a/paddlehub/server/server.py
+++ b/paddlehub/server/server.py
@@ -34,7 +34,7 @@ class HubServer(object):
         elif source_type == 'git':
             source = GitSource(url)
         else:
-            raise RuntimeError()
+            raise RuntimeError('Unknown source type {}.'.format(source_type))
         return source
 
     def _get_source_key(self, url: str):