The present disclosure relates to a communication technique for converging an IoT technology with a 5G communication system for supporting a higher data transfer rate beyond a 4G system, and a system therefor. The present disclosure can be applied to an intelligent service (e.g. a smart home, a smart building, a smart city, a smart car or connected car, healthcare, digital education, a retail business, a security and safety-related service, etc.) on the basis of a 5G communication technology and an IoT-related technology. The present disclosure provides a method wherein, after a MICO mode terminal establishes a connection and transmits data, the MICO mode terminal can be kept in a connected mode state, rather than entering an idle mode, in order to provide for a case where slightly delayed response traffic occurs according to the type of application or service.