The invention discloses a method for genetically transforming agaricus bisporus and relates to the technical field of molecule genetic transformation of the agaricus bisporus. The method disclosed bythe invention comprises the following steps: inoculating agaricus bisporus liquid hyphae into a rice grain culture medium; pre-culturing the rice grain culture medium under the condition that the temperature is 20 to 25 DEG C; culturing until agaricus bisporus hyphae grow on the surfaces of rice grains; uniformly shaking the rice grain culture medium during a pre-culture period. The method disclosed by the invention takes the rice grains as an attachment substrate for the growth of the agaricus bisporus hyphae; the culture substrate is uniformly shaken during the pre-culture period and a co-culture period, so that the hyphae uniformly grow on the rice grains; an impact force generated in a shaking process can be used for enabling the hyphae attached on the rice grains to randomly have wounds, so that the infection of agrobacterium tumefaciens is facilitated and the transformation rate is improved. Compared with an existing genetic transformation method, the method disclosed by the invention has the advantages of convenience for operation, high transformation efficiency and easiness for separating transformants and has a good application prospect.