Abstract: In order to ensure that the return air tunnel in Longwanggou Coal Mine safely passes through the fault that conducts pressure water and blocks the water channel between Ordovician limestone water and the tunnel, to effectively improve the rock strength in the fracture zone of the fault and avoid fault hysteretic water inrush and roof fall accidents caused by the fault, the technology of tunnel passing through the fault was studied by the method of grouting rock strata within 10 m to 30 m below the limestone roof interface of Ordovician period and surrounding rock curtain grouting of the roadway in the fault fracture zone. After the tunnel passes through the fault, the roof of the tunnel in this section has only a small amount of leaching water, and the total amount of leaching water is only 0.5 m³/h. The results show that through grouting treatment of the fault, the channel of Ordovician limestone water is effectively blocked, and the surrounding rock strength of the tunnel is improved, and the treatment scheme can meet the needs of the tunnel safety.