Provided are a method, apparatus and device for a terminal moving between a 4G network and a 5G network. The method includes: transmitting, by a management device corresponding to a target network, an access accept message, where the access accept message carries an activation indication; and the activation indication is used for indicating a terminal to reactivate a public data network (PDN) connection or a protocol data unit (PDU) session in a source network in the target network, or indicating the terminal that the PDN connection or the PDU session has been activated in the target network.