A system, comprising a terminal and a network device, wherein the terminal comprises a processor, a receiver, and a transmitter, and wherein the network device comprises a transmitter, a receiver, and a processor, wherein the transmitter of the network device is configured to send a measurement control message to the terminal, the receiver of the terminal is configured to receive the measurement control message from the network device; the processor of the terminal is configured to: measure a to-be-measured cell indicated in the measurement control message, to obtain a signal measurement value of each cell, and determine, according to the signal measurement value of each cell, whether any candidate cell is adapted to trigger an event 1D or whether any cell is adapted to trigger another intra-frequency measurement event except the event 1D, wherein the to-be-measured cell comprises a candidate cell in an active set, there is at least one candidate cell, and the candidate cell is adapted to preconfigure a resource for the terminal; the processor of the terminal is further configured to: when determining that any candidate cell is adapted to trigger the event 1D, determine a candidate cell that is adapted to trigger the event 1D as a target cell and monitor the target cell, and further configured to: when determining that any cell is adapted to trigger the another intra-frequency measurement event except the event 1D, select, according to a preset rule, a specified cell from a candidate cell whose signal measurement value is greater than that of a serving cell, and monitor the specified cell; the transmitter of the terminal is configured to: when the processor of the terminal determines that any candidate cell is adapted to trigger the event 1D, report a measurement report to the network device, and the transmitter of the terminal is further configured to: when the processor of the terminal determines that any cell is adapted to trigger the another intra-frequency measurement event except the event ID, report a measurement report to the network device, the receiver of the network device is configured to receive the measurement report reported by the terminal; if the measurement report is generated after the terminal determines, according to the signal measurement value of each cell, that any candidate cell is adapted to trigger an event 1D, the processor of the network device is configured to: determine, according to the measurement report, the candidate cell that is adapted to trigger the event 1D as a target cell, and control the target cell to send a change command to the terminal, if the measurement report is generated after the terminal determines, according to the signal measurement value of each cell, that any cell is adapted to trigger another intra-frequency measurement event except the event 1D, the processor of the network device is configured to: determine, according to the measurement report, a target cell from a candidate cell whose signal measurement value is greater than that of a serving cell, and control the target cell to send a change command to the terminal, the receiver of the terminal is further configured to receive the change command from the target cell; and the processor of the terminal is further configured to use a resource of the target cell to perform serving cell change in the target cell according to the change command, wherein there is one specified cell or multiple specified cells, and the target cell is the specified cell or one of the specified cells.