Abstract: The existence of unidentified goaf has induced a variety of mine geological disasters, which poses a major hidden danger to the safe production of coal mines and the safety of people's lives and property. In order to study the law of seismic wave field propagation under the unfavorable geological structure in front of the working face of the roadway, taking the goaf as an example, it is proposed to use the rayleigh channel wave to detect the goaf. Through the establishment of the "rock-coal-rock" three-layer geological model, the numerical simulation of the wavefront characteristics of the seismic advance detection is carried out, respectively, for 80ms,160ms,260ms of X (along the direction of the roadway), Y (vertical side directional direction), and Z (vertical floor direction) and seismic synthetic records of X, Y and Z components are analyzed. The results show that : when the goaf in front of the roadway is detected by seismic advance detection, Rayleigh channel wave can be used as an effective wave to identify the goaf in front of the roadway head; The Rayleigh channel wave has obvious signal characteristics, small interference, strong energy and easy identification on the X and Z components, while the Y-component signal has obvious development of the shear wave, and the Rayleigh channel wave is difficult to identify.