A secondary cell group (SCG) side service processing method includes a master base station that configures a master cell group and an SCG for a terminal device. In uplink and downlink data transmission processes, when link quality information of a serving cell in the SCG meets a first preset condition, the terminal device obtains link quality information of a neighboring cell of the serving cell, determines, based on the link quality information, whether there is a better neighboring cell, and when there is no better neighboring cell, sends a first message to the master base station to enable the master base station to determine, based on the first message, whether to release the SCG.