The disclosure relates to a communication method and system for converging a 5th-Generation (5G) communication system for supporting higher data rates beyond a 4th-Generation (4G) system with a technology for Internet of Things (IoT). The disclosure may be applied to intelligent services based on the 5G communication technology and the IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. A method performed by a terminal in a communication system is provided. The method includes receiving, from a first base station, configuration information for a secondary cell group (SCG) including at least one serving cell associated with a second base station, receiving, from the first base station, a first message for activation or deactivation of the SCG, and in case that the SCG is deactivated based on the first message and uplink data arrives on at least one bearer of the SCG, transmitting a second message for activation of the SCG. According to the disclosure, carrier aggregation and dual connectivity can be quickly activated, thereby reducing battery consumption of a terminal.