The invention relates to a biological preparation for degrading 
pesticide residue in plants and a preparation method thereof, and relates to the technical field of 
agriculture production. The biological preparation solves the problems of poor 
pesticide degradation effects, low degradation speed and no 
broad spectrum of the existing microbial bacterial agents, and is prepared from a 
plant source 
pesticide mixture and a mixed bacterial solution according to the mixture ratio of 3:2, wherein the 
plant source pesticide mixture is prepared from the following materials in parts by weight: 1 to 5 parts of cortex meliae, 1 to 5 parts of radix sophorae falvescentis, 1 to 5 parts of hellebore and 1 to 5 parts of 
mustard seed, wherein the mixed bacterial liquid comprises the following ingredients inparts by weight: 20 to 30 parts of 
bacillus thuringiensis fermentation bacterial liquid, 10 to 15 parts of bacillus brevis lateralis 
fermentation bacterial liquid, 5 to 10 parts of 
bacillus psychrosaccharolyticus fermentation bacterial liquid, 5 to 10 parts of 
bacillus cereus fermentation bacterial liquid, 5 to 10 parts of 
yeast fermentation bacterial liquid, 5 to 10 parts of 
bacillus subtilis fermentation bacterial liquid, 5 to 8 parts of 
bacillus megatherium fermentation bacterial liquid, 30 to 35 parts of 
pseudomonas putidafermentation bacterial liquid and 25 to 30 parts of 
pseudomonas stutzeri fermentation bacterial liquid.