Abstract: Taking low rank coal in Jiaoping mining area for example, the CBM numerical simulation software CBM-SIM was used to study the influence that different coal seam sickness, permeability, gas content, adsorption, reservoir pressure, gas saturation, critical desorption pressure and reservoir pressure ratio will have on CBM well production. The result shows that well production increases with the increase of thickness, permeability, gas content, Langmuir pressure, gas saturation, critical desorption pressure and reservoir pressure ratio, on the contrary, decreases with the increase of Langmuir volume. Reservoir pressure changes only gas producing time and peak time, does not affect well production. Gas saturation, critical desorption pressure and reservoir pressure ratio reflect the changes of well production much better when several factors change.