Roots vacuum pump is a rotary volumetric vacuum pump. Its structure is evolved from a Roots blower. First appearing in Germany in 1944, it was used as a mechanical booster pump to accommodate vacuum melting systems with large pumping speeds in the 10-1000 Pa pressure range. According to Roots vacuum pump working pressure range is divided into straight row of atmospheric vacuum Roots pump; vacuum Roots pump (mechanical booster pump) and high vacuum multistage Roots pump. The largest amount of domestic vacuum Roots pump. Roots vacuum pump compared with other oil-sealed vacuum pumps have the following characteristics: (1) a wide range of pressure in a larger pumping speed; (2) the rotor has a good geometric symmetry, so the vibration is small, stable operation. The rotor and the gap between the rotor and the shell, no lubrication, friction loss is small, can greatly reduce the drive power, which can achieve high speed; (3) no need to seal and lubricate the pump chamber can reduce the oil vapor on Vacuum system pollution; (4) pump cavity without compression, no exhaust valve. The structure is simple and compact, insensitive to the dust and water vapor in the gas being drawn; (5) the compression ratio is relatively low, and the hydrogen pumping effect is poor; (6) the surface of the rotor is a curve cylinder with a complicated shape, and the machining and inspection comparison difficult. Roots vacuum pump in recent years at home and abroad to get faster development. In smelting, petrochemicals, electrician, electronics and other industries have been widely used.