The invention provides a toxicity preventive aquaculture method for penaeus japonicus. The toxicity preventive aquaculture method includes A, removing sludge at the bottoms of aquaculture ponds, spreading quicklime and exposing the quicklime to the sun for 2-3 days; B, laying mixed soil with the thickness of 10 cm at the bottoms of the aquaculture ponds and then exposing the mixed soil to the sun for 2-3 days; C, injecting water into the aquaculture ponds until the depth of the water reaches 50-60 cm, spreading plant ash, cow dung and calcium-magnesium phosphate fertilizers into the aquaculture ponds, allowing the water, the plant ash, the cow dung and the calcium-magnesium phosphate fertilizers to stand still for 10-15 days and then injecting water into the aquaculture ponds until the depth of the water reaches 1.5-1.8 m; D, releasing young penaeus japonicus into the aquaculture ponds and filling the aquaculture ponds with ozone; E, spraying sodium dichloroisocyanurate aqueous solution into the aquaculture ponds at the intervals of 7-10 days in 1-2 months after the young penaeus japonicus is released into the aquaculture ponds so that the concentration of sodium dichloroisocyanurate in the aquaculture ponds is 0.1-0.4%, and continuously spraying the sodium dichloroisocyanurate aqueous solution by 2-3 times. The mixed soil comprises kaolin and fine gravel which are uniformly mixed with each other according to a mass ratio of 1:2. The toxicity preventive aquaculture method has the advantages that the occurrence rate of diseases in aquaculture procedures can be effectively reduced, the aquaculture survival rate can be increased, and the aquaculture quality can be improved.