thanks for ypur reply ..
actually I am adding simple iframe tag to my wordpress post ..the code you are seeing above is the output of the rss feed.
here is the iframe code which is post in my wordpress post
<iframe src="https://www.youtube.com/embed/XWIDLmhbmeA" width="300" height="250" frameborder="0" allowfullscreen="allowfullscreen"/></iframe>
