I am j1 student. i need to get my taxes back. Is it legal for me to use here? I am not a resident. I will apply for visa again so I dont want any problem with taxes.

You are probably an 'exempt individual' because you are here on a J visa- which is a temporary visa and therefore as you say you are considered a Non Resident Alien.

TurboTax doesn't support filing the 1040-NR. They partner with Sprintax. Contact them for more help 

Also here are the IRS guidelines that cover your situation. Be sure to review the 'exempt individual' section

https://www.irs.gov/individuals/international-taxpayers/substantial-presence-test

As a J-1 VISA holder, you are exempt from counting days for the purposes of the 183-day residency formula for five calendar years if you are a student or two calendar years if you are a research scholar or teacher. In this case, you will file a 1040 NR return to report your US -based income only.

Turbo Tax does not support filing 1040 NR returns but our affiliate at Sprint tax does.  Click on the hyperlink provided for further information.