A method for controlling quality of service, including receiving an application programming interface (API) call request that a user terminal is triggered to send when an application (APP) is being used, where the API call request carries a user identifier of the APP and an identifier of the APP, acquiring a quality of service control policy of the APP according to the identifier of the APP and the user identifier of the APP, and controlling, according to the quality of service control policy of the APP, quality of service of a user indicated by the user identifier. Hence, quality of service control can be provided for an APP that registers with an API management device, which improves the APP development efficiency.