Recently，a case of producing feed beyond approval was investigated. In order to effectively strengthen the management of feed production and ensure exercising appropriate supervision over animal husbandry inputs during feed production，its process was analyzed. The investigation method of reverse deduction and forward reasoning for case clues，efficient path for determining the qualification of subjects of offense，key points in collecting evidences and other investigation skills were proposed. At the same time，discussion on whether punishments should be executed towards enterprises and issues concerning the integration and reallocation of enterprise resources were also conducted。