I want to file to USPTO, and I am foreign independent inventor (not American). My question is, do I need to prove micro entity status to uspto? If yes, then how?
No but you do have to swear under penalty of perjury that you qualify as a micro-entity. You use a USPTO form to declare this status. I am not certain but that could possibly jeopardize the validity of any patent that issues on the application later if you are untruthful.