Disclosed is a communication technique for merging, with IoT technology, a 5G communication system for supporting a data transmission rate higher than that of a 4G system, and a system therefor. The present disclosure can be applied to intelligent services (for example, smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail, security, and safety-related services, and the like) on the basis of 5G communication technology and IoT-related technology. The purpose of the present invention is to efficiently transmit downlink data in a slot in which a synchronization signal block is transmitted and, according to the present invention, a base station in a communication system checks whether a synchronization signal block and downlink data are transmitted in the same slot, determines a downlink data transmission method when the synchronization signal block and the downlink data are transmitted in the same slot, and transmits the downlink data and a demodulation reference signal for the downlink data to a terminal on the basis of the downlink data transmission method, and the downlink data transmission method can be determined on the basis of at least one of the transmission pattern of the synchronization signal block, the relationship between the synchronization signal block and a subcarrier interval applied to the downlink data, and the index of the slot in which the synchronization signal block is to be transmitted.