diff --git a/python/paddle/fluid/recordio_writer.py b/python/paddle/fluid/recordio_writer.py
index 8d48e9abef0fb9861284c6302b30efb0e3994989..efe48f4fb39ea760ec44b24e58eba0dde8f40121 100644
--- a/python/paddle/fluid/recordio_writer.py
+++ b/python/paddle/fluid/recordio_writer.py
@@ -36,6 +36,45 @@ def convert_reader_to_recordio_file(
         compressor=core.RecordIOWriter.Compressor.Snappy,
         max_num_records=1000,
         feed_order=None):
+    """
+    Convert a Python Reader to a recordio file.
+
+    Please see :ref:`api_guide_python_reader` and :ref:`api_guide_reader_op` for
+    details.
+
+    Examples:
+
+        >>> import paddle.fluid as fluid
+        >>> import paddle.dataset.mnist as mnist
+        >>> import paddle
+        >>>
+        >>> tmp_program = fluid.Program()
+        >>> with fluid.program_guard(tmp_program):
+        >>>     img = fluid.layers.data(name='img', shape=[784])
+        >>>     label = fluid.layers.data(name='label', shape=[1], dtype='int64')
+        >>> feeder = fluid.DataFeeder(feed_list=[img, label], place=fluid.CPUPlace())
+        >>> # mnist.recordio will be generated in current directory
+        >>> fluid.recordio_writer.convert_reader_to_recordio_file(
+        >>>                     filename="mnist.recordio",
+        >>>                     reader_creator=paddle.batch(mnist.train(), batch_size=32),
+        >>>                     feeder=feeder)
+
+    Args:
+        filename(str): The recordio filename.
+        reader_creator(callable): The Python Reader Creator. See
+            :ref:`api_guide_python_reader`.
+        feeder(DataFeeder): The DataFeeder instance. Used to convert
+            :code:`reader_creator` to :code: `lod_tensor`
+        compressor: Must in fluid.core.RecordIOWriter.Compressor.Snappy or
+            fluid.core.RecordIOWriter.Compressor.NoCompress. Use :code:`Snappy`
+            by default.
+        max_num_records(int): Maximum number of records in one chuck. Each record
+            is each return value from reader function
+        feed_order(list): The order of variable names that the reader returns
+
+    Returns:
+        int: the number of record that saved.
+    """
     if feed_order is None:
         feed_order = feeder.feed_names
     counter = 0
@@ -58,6 +97,13 @@ def convert_reader_to_recordio_files(
         compressor=core.RecordIOWriter.Compressor.Snappy,
         max_num_records=1000,
         feed_order=None):
+    """
+    convert a python reader to many recordio files.
+
+    This API is basically same as :code:`convert_reader_to_recordio_file`,
+    instead of it will create many recordio files. Each file contains at
+    most :code:`batch_per_file` records.
+    """
     if feed_order is None:
         feed_order = feeder.feed_names
     f_name, f_ext = os.path.splitext(filename)
diff --git a/python/paddle/fluid/trainer.py b/python/paddle/fluid/trainer.py
index f2ae63b5118cacfa2836582fb3d2d262a6434fe4..1728d48a2bc83de8bcc25549161dcaf86be809be 100644
--- a/python/paddle/fluid/trainer.py
+++ b/python/paddle/fluid/trainer.py
@@ -33,6 +33,13 @@ __all__ = [
 
 
 class BeginEpochEvent(object):
+    """
+    The begin of a training epoch.
+
+    Args:
+        epoch_id(int): The current epoch ID.
+    """
+
     def __init__(self, epoch_id):
         self.epoch = epoch_id
 
@@ -50,10 +57,22 @@ class EndEpochEvent(object):
 
 
 class BeginStepEvent(object):
+    """
+    The begin of a training epoch.
+
+    Args:
+        epoch_id(int): The current epoch ID.
+        step_id(int): The current step ID.
+    """
+
     def __init__(self, epoch_id, step_id):
         self.epoch = epoch_id
         self.step = step_id
         self.fetch_metrics = True
+        """
+        If fetch_metrics is true, the metrics will be fetched at the 
+        EndStepEvent. Default is True.
+        """
 
 
 class EndStepEvent(object):
diff --git a/python/paddle/fluid/unique_name.py b/python/paddle/fluid/unique_name.py
index 33c53113ae7e8ed9aeada31f2aed6990b6fea110..776619cd36722e338a9fdd5e13bceeaf3724de2c 100644
--- a/python/paddle/fluid/unique_name.py
+++ b/python/paddle/fluid/unique_name.py
@@ -16,7 +16,7 @@ import collections
 import contextlib
 import sys
 
-__all__ = ['generate', 'switch', 'guard', 'UniqueNameGenerator']
+__all__ = ['generate', 'switch', 'guard']
 
 
 class UniqueNameGenerator(object):