The invention discloses a cooker lid. The cooker lid comprises a cooker lid body, an ultraviolet sterilization module and a steam valve, wherein the steam valve comprises a valve seat arranged on the cooker lid body and a bonnet mounted on the valve seat, and an exhaust channel is formed between the valve seat and the bonnet; the ultraviolet sterilization module is arranged in the steam valve and can emit ultraviolet light to irradiate the exhaust channel of the steam valve. The invention further discloses a cooker. The cooker comprises a cooker body and the cooker lid, wherein the cooker lid body is arranged on the cooker body to cover the cooker body. The invention further discloses a preservation method for food in the cooker. According to the method, after food cooking, a control device controls an ultraviolet lamp in the steam valve to be switched on, and the ultraviolet lamp emits ultraviolet light which penetrates an ultraviolet light transmitting piece to irradiate the exhaust channel in the steam valve. The cooker lid, the cooker and the preservation method for the food in the cooker have the advantages that the sterilization efficiency is high, and bacteria can be inhibited from invading the food in the cooker.