Abstract: The paper introduces the outburst prevention principle of advancing emission hole,and elaborates on the measurement method and the applicable conditions of the effective radius in detail.According to the characteristics of hardness and thickness of 3^# coal seam in Pingshang coal mine,the paper innovates existing borehole gas flow measuring emissions hole method.Using this method,effective emission radiuses of advancing hole with different diameter in 3^# coal seam are got,which provides the basis for the design of mine local prevention outburst emission,and improves the outburst prevention measures results.