The invention relates to a 
crop soil purifying agent and a preparing method thereof, and belongs to the technical field of purifying of 
pesticide and heavy 
metal residues in 
crop soil. The 
crop soil purifying agent is prepared from, by weight, 2-15 parts of a 
flos daturae extraction solution, 10-50 parts of a liquorice extraction solution, 1-10 parts of a henbane extraction solution, 2-15 parts of a 
scutellaria baicalensis extraction solution, 2-15 parts of a radix sophorae flavescentis extraction solution, 1-10 parts of a Chinese 
mahonia extraction solution, 0.05-0.3 part of 
calcium disodium 
ethylene diaminetetracetate and 0.5-1 part of 
sodium thiosulfate. According to the crop soil purifying agent and the preparing method, the specific 
traditional Chinese medicine extraction solutions and the other specific raw materials are combined in cooperation with the specific ratio to prepare the soil purifying agent, use of fertilizers and 
pesticide in the farming growing period is not influenced by the purifying agent, the farming procedure is not changed, and the yield of crops is not influenced and even can be increased. After the soil purifying agent is used, no 
pesticide residue of the crops can be completely achieved, and the content of heavy 
metal is also greatly reduced.