Welcome to SolidWorks forums Taghi.
There is no direct way to do that. You can save the SW2012 files as IGES, Parasolid, etc. and then open in the SW2010. Then use FeatureWorks (an add-in under Tools > Add-In) to convert some of the feature. Else recreate the files in SW2010.
You might also find this post helpful for your future reference.
Hi mr. Deepak Gupta
i knew this solution .
anyway thank you for your answer.