The invention discloses a wall hanging furnace three-way valve control device and an assembling and connecting method thereof. The wall hanging furnace three-way valve control device comprises an upper cover and a lower cover, a mounting space defined by the upper cover and the lower cover is internally provided with a mounting plate arranged on the lower cover , a bathroom microswitch, a heatingmicroswitch, a PCB, a motor arranged between the lower cover and the mounting plate, an ejection piece movably arranged on the side, close to the upper cover, of the mounting plate and a driving cam,wherein the bathroom microswitch, the heating microswitch and the PCB are arranged on the mounting plate; the bathroom microswitch and the heating microswitch are located between the mounting plate and the upper cover and located on one side of the PCB; the PCB is connected with the bathroom microswitch and the heating microswitch through an electric wire, and a lead of the motor is connected withthe PCB; and the ejection piece penetrates through the upper cover, the driving cam is located on one side of the bathroom microswitch and the heating microswitch, and the driving cam is connected with an output shaft, which penetrates through the mounting plate, of the motor and is abutted against the ejection piece. According to the device and the method, three 250 terminals are replaced by thePCB, so that the installation difficulty is reduced, and the assembly efficiency is improved.