Provided is a tracking area assignment method by an access and mobility management function (AMF) in a wireless communication system. The method may include receiving, from a session management function (SMF), service and session continuity (SSC) mode indication information for a protocol data unit (PDU) session generated for a user equipment (UE), obtaining serving area information for a serving area of a serving user plane function (UPF) associated with the PDU session, determining the assignment of a new tracking area to the UE is necessary based on a tracking area pre-assigned to the UE and the serving area, and performing tracking area update for the assignment of the new tracking area to the UE if it is determined that the assignment of the new tracking area is necessary.