Abstract: Small totally enclosed helium compressor is a componend equipment of G-M refrigerator.It is widely used in space environment simulation equipments、vacuum cryopump and vacuum coating equipments etc. At present,almost all small enclosed heliuin compressor were remade from the enclosed freon refrigerator.This paper discusses how to solve the problems of cooling of compression,lubricating and gas purification in different working gas and operating condition.That can use freon compressor to compress helium gas and ensures the safety、reliability、long-life operation of helium compressor.