The invention relates to a non-cleavage preparing method of cavity surfaces of a side emitting semiconductor laser. The method is characterized by comprising the steps of designing and generating a specific material structure of the laser, preparing a resonance cavity mask graph of the laser by using a photoetching method, selecting specific corrosive liquid according to the material structure of the laser, etching the resonance cavity, then performing lateral etching on a corrosion sacrificial layer with selective corrosive liquid to form a cantilever structure at the cavity surface of the laser, and forming a front cavity surface and a rear cavity surface of the laser by breaking the cantilever structure via supersonic. According to the method for preparing the front and rear cavity surfaces of the laser, the cavity surfaces with high quality of the laser can be formed without the need of cleavage of a substrate. The method can be used for forming the cavity surfaces of the laser under the specific conditions that the substrate of the laser is hard subjected to cleavage to form a high-quality cleavage surface, the substrate of the laser cannot be subjected to cleavage due to specific demands or the like.