An operation method of a terminal in a communication system includes receiving bandwidth part (BWP) change information from a base station in a BWP i; changing an operation BWP of the terminal from the BWP i to a BWP j even when a transmission and reception procedure of first data in the BWP i is not completed at a BWP changing point indicated by the BWP change information; and performing a data transmission and reception procedure of second data in the BWP j, wherein the BWP i and the BWP j are different BWPs, and i and j are different integers.