The invention discloses a Blumea balsamifera (L.) DC. residue culture medium capable of lowering the malformation rate of Pleurotus ostreatus and a cultivation method capable of lowering the malformation rate of Pleurotus ostreatus and belongs to the technical field of edible fungi. The culture medium comprises, by weight, 35-48 parts of cotton seed hull, 40-70 parts of Blumea balsamifera (L.) DC.residues, 10-20 parts of wheat bran, 0.5-1.5 parts of gypsum powder, 0.5-1.5 parts of lime power and 0.5-1.5 parts of sucrose, wherein the Blumea balsamifera (L.) DC. residues are plant residues obtained after steam distillation extraction is performed on Blumea balsamifera (L.) DC. to extract Blumea balsamifera (L.) DC. pieces. The cultivation method includes: activating strains, preparing production strains, preparing the culture medium, inoculating and performing spawn running. The culture medium and the cultivation method have the advantages that the Blumea balsamifera (L.) DC. residues are used to replace sawdust, the cultivated Pleurotus ostreatus is high in yield and low in malformation rate, production cost is lowered, and economic benefits are increased effectively.