Abstract: Through in-situ measurement of gas drainage parameters (negative pressure, flow and concentration) in belt main entry and another entry of 3^# coal seam No. 2 mining area in Fuyan Coal Mine, the relation between gas drainage negative pressure and pure flow is studied. Research results show that the relation between gas drainage negative pressure and pure flow can be described by three times power function,q=Ap³+Bp²+Cp+D, the optimal negative pressure range of drainage hole is from 40 to 45 kPa.