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. The present disclosure provides a user equipment and a base station in a wireless communication system and methods performed by the same. The method performed by the user equipment includes: determining a third timing advance based on a first timing advance configured by a base station and/or a second timing advance estimated by the user equipment, wherein the third timing advance is used for physical random access channel (PRACH) transmission of an initial random access procedure; receiving a timing advance control command indicated by the base station through a random access response (RAR); and obtaining a fourth timing advance according to a timing advance indicated by the timing advance control command and the third timing advance.