is making reports using stored procedures is good practice or using expression rule ?? which is best and why?

I would always recommend using records or expression rules for reporting. 

There is not general answer to this question. Yes / No / Maybe ...

I would be curious as to the needs.. It could be about what you are making the user "wait" for.

If your report needs to dynamically create a SQL to execute and get the data - then sure a stored proc
If your report is manipulating data - then use a view
If your report is pulling data from a table - use a table

Using a stored proc for a report is a maybe (but should not be often)