It was couple years ago,my friend involved in a criminal case(he said it's theft under 5000),and he left canada without going to the police station for fingerprint/photograph thing,since then,police will issue an arrest warrant against him.
In this situation,can he still enter the US or other countries without any problem?

No, if there is a warrant out for him, he will be detained while they check with the courts there if they want to have him returned