Abstract: The protection system of small intelligent flameproof vacuum magnetic starter used in mine which is composed of 80C196KC single chip microcomputer of MCS 96 series was introduced, in which short circuit protection, open phase protection, overload protection were realized by software. Particularly, the function of fault locking settled the problem which causes electric spark after power on because of short circuit, open phase, leak electricity before power on, thus avoiding causing coal dust or gas explosion accidents. The system was proved through the lab simulating test that all its indexes satisfled the demands of design and achieved good results.