Abstract: In order to accurately evaluate the drainage effect of surface coalbed methane horizontal wells and grasp the occurrence status of residual coalbed methane（coalbed methane）,a technical process is proposed to evaluate the drainage effect of coalbed methane wells by implementing directional drilling sampling from the underground mining space of coal mines to the affected area of coalbed methane wells, in response to the practical problems of large engineering quantity, long cycle, and high cost of surface parameter wells.Based on the inversion and numerical simulation results of the gas discharge and extraction data of the surface coalbed methane segmented fracturing horizontal well in coal mine, combined with the actual underground mining layout of coal mine, 7 directional long boreholes with different depths are designed to be arranged in the gas extraction roadway of the east wing underground.The minimum vertical distance between the sampling points of the boreholes and the horizontal well section is 35 m.The underground coal seam long-distance fixed-point sealed core sampling technology and device are adopted, Equipped with a ZDY6000LD directional drilling rig and a mud pulse measurement system that facilitates closed core sampling for drilling and fixed-point closed core sampling.The test results of coal seam sealed core gas content show that the coal seam gas content in the area with a shallow horizontal distance of 70～117 m in the horizontal well section is 5.09～9.85 m³/t.After comparing and analyzing the results of the original coal seam gas content measurement in the area before extraction, the radius of influence of horizontal well extraction in this surface well group is 117 m.