In an aspect of the present invention, a method for performing a service request message of an Access and Mobility Management Function (AMF) in a wireless communication system may include a packet data unit (PDU) session identifier (ID) for a PDU session whose activation is desired by a user equipment from the user equipment; transmitting a first message comprising the PDU session ID to a session management function (SMF); when an establishment of the PDU session is rejected by the SMF: receiving a second message comprising a reject cause of the PDU session establishment as a response to the first message; and transmitting a service response message comprising the reject cause and a PDU session ID rejected by the reject cause to the user equipment.