Abstract: There is a close relationship between protective coal pillar size and supporting parameters. Based on the unified strength theory, we establish the calculation model between supporting stress and protective coal pillar size. The model shows that the larger supporting stress, the smaller the size of the pillar. Through the numerical simulation, different anchor belt mesh support parameters show supporting stress in the lane for vertical, horizontal and overall surface distribution. Based on supporting result and the difficulty of construction, we choose the optimal anchor belt net support parameters. According to calculation, the mine 7212 working face roadway supporting pillar is 7 m. Engineering practice shows that the roadway can be effectively controlled.