Is any law or department can protect international students or help them solve problems during they study in America?
There is no special government agency to help foreign students with legal problems.
The above is intended only as general information, and does not constitute legal advice. You must speak with an attorney to discuss your individual case.
It depends on what "problems" the international student has. If there is a threatening situation to your person or property, you can always call 911.
Your question is not very clear.