According to the different exhaust pressure compressor can be divided into low-pressure compressor, exhaust pressure less than 1.0MPa; medium-pressure compressor, exhaust pressure 1.0MPa ~ 10MPa; high-pressure compressor? Discharge pressure 10MPa ~ 100MPa; ultra-high pressure compressor? Discharge pressure greater than 100MPa and so on. Low-pressure compressor for the single-stage type, medium pressure, high pressure and ultra-high pressure compressor for the multi-stage type, the most number of machines up to 8 levels, has been made in foreign countries with a pressure of 343MPa polyethylene with the ultra-high-pressure compressor. According to the different compression medium, the general compressor can also be called: air compressor, oxygen compressor, nitrogen compressor, hydrogen compressor and so on.