The invention relates to the technical field of communications, and more particularly, to a method and device for realizing synchronization. The method comprises: performing, by a base station, and according to an SRS signal transmitted by a terminal, filtering to obtain a RRU channel having the maximum receiving power in a current operation; upon determining that the RRU channel having the maximum receiving power in the current operation is different from a RRU channel used in the currently performed demodulation, refraining from performing immediate switching; and permitting switching of the RRU channel only when the receiving power of the RRU channel is determined to match the maximum threshold of a preset series of thresholds, and transmitting a TA command word to the terminal while switching the RRU channel to complete synchronization with the terminal. The invention prevents a terminal from frequently switching between RRU channels on a subframe basis. Moreover, a TA command word is transmitted while switching is being performed, thereby preventing a problem in which when a change in a RRU channel occurs, a TA command word is not received by a terminal for a long time, resulting in an asynchronous operation.