How do I fetch user profile data in search api entity (node) view? I've one search api index view of node type. Then each user have profile. So I wanted to fetch profile data of that entity created user. In normal view it can be easily done with relationship. But in search api view not able to create relationship. Any idea?

Same way I wanted flag relationship also but it's not happening in search API view. Normal view it's fine.
Your search api view is only able to list what has been indexed, so you should add the node author to the search api index.

After this, in search api, you should be able to add 'related fields'. 

After adding items to be indexed in search api, make sure you reminded your site!