The seismic wave field in layered coal seam is simulated with coal road model. Propagation characteristics of seismic wave in horizontally stratified coal seam are analyzed. The results showed: 1) the P-wave source in the coal bed floor before coal heading face can excite Rayleigh channel wave in coal seam; and 2) the Rayleigh channel wave generates reflected Rayleigh channel wave on the small structure before coal heading face. The energy of vertical component of Rayleigh channel wave is stronger than horizontal component energy; and 3) in same conditions, the method of reflected-wave seismic prediction ahead is not applicable for detecting small structure before coal heading face. The energy of reflection waves from the interfaces of small structure before coal heading face is very low.