The invention relates to a diseases-prevention organic fertilizer prepared by edible fungi residue, comprising the following steps of: adding trichoderma fermentation liquid into decomposed edible fungi residue, and preparing trichoderma fermentation substance; adding actinomycete fermentation liquid into decomposed edible fungi residue, and preparing actinomycete fermentation substance; evenly mixing the trichoderma fermentation substance and the actinomycete fermentation substance according to the mass ratio of 0.5-1:0.5-1; and airing the obtained mixture until the moisture content is 20-22% at the normal temperature; wherein the decomposed edible fungi residue is prepared by stacking and fermenting 75-85 parts of edible fungi residue, 15-20 parts of cake and 1-2 parts of microbial fermentation fungicide, and airing until the moisture content is 25-35%. The diseases-prevention organic fertilizer has high effective component, good diseases-prevention effect, safety, environmental protection and low cost.