Abstract: With the increasing mining intensity of steeply dipping seam, the occurrence of flying gangue disasters has become more and more common. In the mining of steeply dipping seam, flying gangue will threaten the people and equipment of mining face in various forms of movement.In order to improve the safety of the working surface system and reduce the threat of the flying gangue to the operators and equipment of the mining face, the movement characteristics of the flying gangue were studied.Through the analysis of the actual working condition of a working face, the influencing factors, the trajectory of movement and the interaction between the flying gangue and the working face caused by the roof leakage are analyzed. Using Roc Fall software, the flying gangue movement model is established, the characteristics of the flying gangue sliding motion are analyzed, and the position of the flying gangue prevention and control is predicted.According to the simulation results, the protective devices are built near the horizontal positions of 16.27 m and 55.57 m at the starting point of the working face.An automatic pneumatic gangue retaining device is designed according to the instantaneous velocity of flying gangue in the protective position.The SNS flexible net is used as the protective net and is mounted on the pneumatic gangue retaining device. Combining with the simulation data, the interception range of flying gangue in the mining face is determined, and the number and location of the gangue retaining devices are arranged. According to the instantaneous speed of flying gangue at the interception point and the scope of the working face that needs protection, the pneumatic gangue retaining device designed by grating early warning can effectively protect flying gangue, which has certain application value.