A communication technique of fusing a fifth generation (5G) communication system for supporting higher data transmission rate beyond a fourth generation (4G) system with an Internet of things (IoT) technology and a system thereof are provided. The communication technique may be used for an intelligent service (for example, a smart home, a smart building, a smart city, a smart car or a connected car, health care, digital education, a retail business, a security and safety related service, or the like) based on the 5G communication technology and the IoT related technology. A method for defining media access control (MAC) sub-header structures suitable for a next generation mobile communication system and applying the MAC sub-header structures to provide a high data transmission rate and a low latency in the next generation mobile communication system is provided.