The embodiment of the invention provides a method and apparatus for multiplexing a channel of an unlicensed frequency band. The method comprises the following steps that: when data to be transmitted exist, channel energy in a detection frame is detected, and the proportion alpha of the occupation time of a current Wi-Fi station on a channel in the detection frame is obtained; the first number of sub frames in a first transmission frame which are occupied by an LAA base station in a transmission period is obtained according to the alpha, the service type of the data to be transmitted and a first preset formula, and the sub frames of the first number are adopted to perform data transmission; and the second number of sub frames in an another transmission frame which are occupied by the LAA base station is determined according to the number of confirmation messages which are obtained after the data in the previous transmission frame are transmitted, and a second preset formula, and the sub frames of the second number are adopted to perform data transmission. With the method and apparatus of the invention adopted, fairness and efficiency of channel multiplexing of the LAA base station and the Wi-Fi station can be considered.