In a connection reactivation method, a connection of a PDU session established by user equipment on a N3GPP side is reactivated through communications via a 3GPP network. The user equipment accesses both the 3GPP and the N3GPP network and is originally in an idle state on the N3GPP network. An access and mobility management function entity receives a first message from a session management function entity to reactivate the PDU session connection of the user equipment. The access and mobility management function entity sends a second message to the user equipment via the 3GPP access network to instruct the user equipment to reactivate the connection of the PDU session.