The invention relates to a dynamic identification access control system, in particular to a WISP tag based user-defined gesture identification access control system and an identification method. the system comprises a WISP tag based access control card, a tag reader based access control sensing device and a computer based background device, wherein the access control sensing device and the background device are connected through a cable, a card housing of the access control card is selected from a plastic container, a WISP tag is put in the plastic container, is integrated with a triaxial accelerometer and is burned with a program capable of extracting numerical values of the triaxial accelerometer. The WISP tag based user-defined gesture identification access control system permits a user to define an identification action by himself/herself, and the practicability and safety of the access control system are improved. When an unauthorized user needs to temporarily enter the access control system, an authorized user can complete authorization transfer between the users only by telling the unauthorized user the user-defined identification action defined by the user.