Abstract: Coalbed gas production characteristics determine that the coalbed gas entering flowline also contains impurities such as water and dust, pressure drop loss of gas during flow process induced by water and solid particles will be inevitably.Therefore, the paper uses test loop to simulate the flow characteristics of multiphase medium of coalbed gas flowline, and investigates the pressure drop characteristics of gas-liquid flow and gas-solid flow. The conclusions are that gas flow rate in coalbed gas flowline should be limited within from 4 m/s to 8 m/s, and measures like pigging should be taken to reduce the build-up of sediments, and hydraulic calculation of gas flowline can neglect the effect of solid particles, but take gas-liquid pressure drop calculation method.