Different from oil wells, CBM wells mainly rely on drainage and pressure reduction. During the production process, there are many impurities in the coal seam water, which are corrosive and have a high gas-liquid ratio, and the water production in the previous and subsequent periods varies greatly. According to this working situation, the special Screw pump for CBM was designed based on the continuous experimental demonstration and optimization improvement of the conventional Screw pump. Because it operates at a uniform speed, there is no inertia loss of machinery and fluid flow, It can be applied not only to the production of general coalbed methane wells, but also to the production of coalbed methane wells with high gas content and high powder coal content (fly ash content ≤ 30%), ensuring the continuous and stable discharge of coalbed methane wells. At the same time, coalbed methane Screw pump has a series of advantages such as high efficiency, low energy consumption, simple structure, low price, small size, easy operation, etc.