The present 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 present 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 base station, configuration information on a configured grant for uplink transmission, the configured grant being configured with an autonomous transmission; in case that a previous configured grant for a hybrid automatic repeat request (HARQ) process was not prioritized, a transmission of a first medium access control (MAC) protocol data unit (PDU) obtained for the HARQ process has not been performed, and a size of the first MAC PDU matches a size of a configured grant, identifying that the first MAC PDU has been obtained for the configured grant; and in case that the configured grant is a prioritized uplink grant, delivering the obtained first MAC PDU.