The present invention provides a novel cow superovulation sustained-release agent, which is a hyaluronic acid solution with a concentration of 5.0-10.0 mg/mL. According to the present invention, with the combination of the cow superovulation sustained-release agent and FSH, the FSH action effect is prolonged, the cow superovulation process is simplified, the superovulation efficiency is improved, and the superovulation effect equal to the conventional superovulation effect can be obtained, wherein 8 injections within 4 days is reduced to 2 injections within 4 days; and the operation of the method is simple, the superovulation efficiency is improved, and the method is easy to operate at the cow farming site and is easy to promote and use.