A manufacturing method of plastic snowboard featured by the steps as follows: making the inner core (3) in the shape of the product by steam heating in the foaming mold, manufacture of the bottom board (6), manufacture of the compound bottom board and the surface board (7), forming the surface board (7) and the compound bottom board, trimming, then sealing the edge of the product by hot melting to get the molded product. Compared with existing techniques, the advantages of this invention are that it firstly make the inner core in the shape of the product by steam heating in the foaming mold, which improves the impact resistance, and that the inner core acting as the framework is formed in the mold separately, making the framework of the inner core stronger, and that in case of external force, the inner core will have fine elastic deformation and stronger impact resistance, which prevents the product from deformation and thus greatly enhances the impact resistance of the product.