A speaker box assembly includes two speaker boxes, two line-winding means, a switch, and a power supply unit. Each of the two speaker boxes is provided on its surface with an outlet hole. One of the two speaker boxes is provided on its surface with a connector jack. The two line-winding means are provided in the two speaker boxes respectively. Each of the line-winding means has a line-winding box and an electrical line. The line-winding box is located inside the speaker box. The inner end of the electrical line is connected to the line-winding box, and the outer end of the electrical line is connected to a connector member. The connector member and the electrical line pass through the outlet hole selectively. The connector member in one of the speaker boxes is inserted into the connector jack on the other of the speaker boxes.