Abstract: The paper anlyzes gas prevention and gas emission laws of lower protective layer 11223 working face in Jinjia Mine. After five months of gas control, the maximum residual gas pressure is 0.36 MPa, the maximum residual gas content is 5.19 m³/t, average gas extraction rate is 89.24%. On this basis, the paper analyzes the impact of working face gas emission form, key stratum, crack, roof pressure on gas emission.