The invention relates to the technical field of aquaculture, in particular to a pharmaceutical composition for promoting aquatic animal ovulation and an agent and method thereof. The pharmaceutical composition is composed of phenylalanine, hydroxymethyl glutaryl, potassium nitrate, calcium chloride and urine of pregnant animals. The pharmaceutical composition can remarkably promote the ovulation of ampullaria gigas and other aquatic animals; compared with the contrast, the ovulation amount can be increased by 34-36%, and the ovulation time interval can be shortened by 4-5 days. By means of themethod, the ovulation of ampullaria gigas and other aquatic animals can be promoted, breeding cost can be saved, and the economic benefits of farmers are improved.