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 homes, smart buildings, smart cities, smart cars, connected cars, health care, digital education, smart retail, and security and safety services. A method and an apparatus for transmitting or receiving a synchronization signal block in a wireless communication system which operates in an unlicensed band are provided. The method includes a method for configuring a synchronization signal block time resource and index by a node which is to transmit a synchronization signal block in an unlicensed band, and a method for determining a synchronization signal block index and acquiring time synchronization by a node which receives a transmitted synchronization signal block.