The invention discloses a mechanical activation-metal salt reinforcement-combined starchy raw material saccharification method. The method comprises 1, raw material treatment: removing impurities in starchy raw materials, drying the starchy raw materials until water content is less than 25%, carrying out crushing and carrying out screening through a sieve of 40-100 meshes, 2, mixing: mixing the treated starchy raw materials and a metal salt according to a weight ratio of 100: 0.5-5 to obtain a uniform mixture, 3, mechanical activation reaction: putting the uniform mixture into a mechanical activation reactor, carrying out treatment at a mechanical activation temperature of 25-60 DEG C for 10-180min and carrying out ball material separation to obtain the activated starchy raw material, 4, slurry preparation: putting the activated starchy raw material into a slurry preparation tank and adding water into the activated starchy raw material at a temperature of 30-50 DEG C along with stirring so that the activated starchy raw material is stirred and dissolved to form starch slurry with a concentration of 25-40%, and 5, saccharification: putting the raw material slurry into a saccharification tank, adding glucoamylase into the saccharification tank and carrying out saccharification to obtain a saccharification liquid.