Abstract: The adaptive control based on a series of Least-Squares algorithms can only be suitable for the processes with known and constant time delay. In this paper, an identification algorithm which can estimate time-varying delay and other parameters of processes is proposed. It will make the method of Least-Square identification and adaptive control used in a larger realm. An application example of the proposed algorithm in adaptive control system design is given, and the further study on this topic is discussed as well.