A method for session reestablishment, applied to an Access and Mobility Management Function entity AMF, and comprising: obtaining a Non-Access Stratum NAS message transmitted by a terminal, wherein the NAS message is used to request to establish a new packet data unit PDU session connected to a same data network as an initial PDU session, and the NAS message carries first identification information of the initial PDU session and second identification information of the new PDU session assigned by the terminal; and transmitting a session management request to a Session Management Function entity SMF corresponding to the first identification information, wherein the session management request carries the first identification information and the second identification information, and the session management request is configured to cause the SMF to establish the new PDU session in accordance with the first identification information and the second identification information, wherein the transmitting the session management request to the SMF corresponding to the first identification information comprises: parsing the NAS message to obtain the first identification information; obtaining SMF identification information corresponding to the first identification information in accordance with a pre-stored correspondence between identification information of PDU sessions and identification information of SMFs; and transmitting the session management request to the SMF corresponding to the SMF identification information, characterized by that the NAS message is used to initiate a PDU session reestablishment request, and PDU session identification information in the PDU session reestablishment request carries the first identification information and the second identification information; and the parsing the NAS message to obtain the first identification information comprises: parsing, by the AMF, the PDU session identification information in the PDU session reestablishment request to obtain the first identification information and the second identification information. obtaining a Non-Access Stratum NAS message transmitted by a terminal, wherein the NAS message is used to request to establish a new packet data unit PDU session connected to a same data network as an initial PDU session, and the NAS message carries first identification information of the initial PDU session and second identification information of the new PDU session assigned by the terminal; and transmitting a session management request to a Session Management Function entity SMF corresponding to the first identification information, wherein the session management request carries the first identification information and the second identification information, and the session management request is configured to cause the SMF to establish the new PDU session in accordance with the first identification information and the second identification information, wherein the transmitting the session management request to the SMF corresponding to the first identification information comprises: parsing the NAS message to obtain the first identification information; obtaining SMF identification information corresponding to the first identification information in accordance with a pre-stored correspondence between identification information of PDU sessions and identification information of SMFs; and transmitting the session management request to the SMF corresponding to the SMF identification information, characterized by that the NAS message is used to initiate a PDU session reestablishment request, and PDU session identification information in the PDU session reestablishment request carries the first identification information and the second identification information; and the parsing the NAS message to obtain the first identification information comprises: parsing, by the AMF, the PDU session identification information in the PDU session reestablishment request to obtain the first identification information and the second identification information. parsing the NAS message to obtain the first identification information; obtaining SMF identification information corresponding to the first identification information in accordance with a pre-stored correspondence between identification information of PDU sessions and identification information of SMFs; and transmitting the session management request to the SMF corresponding to the SMF identification information, characterized by that the NAS message is used to initiate a PDU session reestablishment request, and PDU session identification information in the PDU session reestablishment request carries the first identification information and the second identification information; and the parsing the NAS message to obtain the first identification information comprises: parsing, by the AMF, the PDU session identification information in the PDU session reestablishment request to obtain the first identification information and the second identification information.