Abstract: Aiming at the disaster of water and sand inrush in the first working face of improving mining upper limit of Renlou Mine, this paper analyzes the causes combined with the overburden structure, strata behaviors and support resistance. The results show that wind lane roof damage and occurred instability along the laneway's side lead to the roof lateral support structure disappeared. Lack of support resistance, not timely support in overall breaking of the overlying strata during periodic weighting period leads to the structural instability of overburden rock masonry beam, serious leakage at the end face, which causes serious water and sand inrush. In the latter repeated mining process, improving support resistance, repairing deformed wind lane, changing the support form of roadway and improving drainage systems and strengthening the support management of working face are main means to prevent the water and sand inrush.