A mobility management method, performed by an NG-RAN, Next Generation-Radio Access Network, installed in a satellite of a satellite internet system, wherein the mobility management method comprises: sending, to a terminal, a configuration message for the terminal to carry out neighbor cell signal measurement and position measurement, such that the terminal reports, according to the configuration message, neighbor cell signal strength or terminal position information, wherein the terminal position information comprises GPS, Global Positioning System, position information of the terminal; determining, according to position information of the NG-RAN and a measurement report, whether a specified condition allowing the terminal to carry out a neighbor cell handover is satisfied, after the measurement report, which is reported by the terminal and comprises the neighbor cell signal strength or the terminal position information, is received; and sending a cell handover message to the terminal to handover the terminal from a current cell to a target cell, if the specified condition allowing the terminal to carry out the neighbor cell handover is satisfied, wherein the specified condition is a condition allowing the terminal to carry out the neighbor cell handover; characterized in that, the configuration message is sent to the terminal and is used for the terminal to carry out neighbor cell signal measurement and terminal position information measurement, and the configuration message comprises: information of a third neighbor cell of a ground mobile network, such that the terminal carries out cell handover between the satellite internet system and the ground mobile network, wherein a beam of the third neighbor cell is a beam corresponding to the target cell, and the ground mobile network is adjacent to the NG-RAN of the satellite internet system; the terminal position information, or terminal moving information and the terminal position information, wherein the terminal moving information comprises moving speed, a moving direction and a type of the terminal; and a reporting occasion of the configuration message, wherein the reporting occasion is a moment in the condition that a moving state of the terminal is rapidly changed or a reporting period. sending, to a terminal, a configuration message for the terminal to carry out neighbor cell signal measurement and position measurement, such that the terminal reports, according to the configuration message, neighbor cell signal strength or terminal position information, wherein the terminal position information comprises GPS, Global Positioning System, position information of the terminal; determining, according to position information of the NG-RAN and a measurement report, whether a specified condition allowing the terminal to carry out a neighbor cell handover is satisfied, after the measurement report, which is reported by the terminal and comprises the neighbor cell signal strength or the terminal position information, is received; and sending a cell handover message to the terminal to handover the terminal from a current cell to a target cell, if the specified condition allowing the terminal to carry out the neighbor cell handover is satisfied, wherein the specified condition is a condition allowing the terminal to carry out the neighbor cell handover; information of a third neighbor cell of a ground mobile network, such that the terminal carries out cell handover between the satellite internet system and the ground mobile network, wherein a beam of the third neighbor cell is a beam corresponding to the target cell, and the ground mobile network is adjacent to the NG-RAN of the satellite internet system; the terminal position information, or terminal moving information and the terminal position information, wherein the terminal moving information comprises moving speed, a moving direction and a type of the terminal; and a reporting occasion of the configuration message, wherein the reporting occasion is a moment in the condition that a moving state of the terminal is rapidly changed or a reporting period.