The optical coupler module for converting and transmitting electrical/optical signals includes a semiconductor substrate, a first film, a second film, an electrical transmission unit, at least one signal conversion unit and an optical waveguide structure. The first film and the second film are formed on opposite surfaces of the semiconductor substrate. The signal conversion unit and the optical waveguide structure are disposed on opposite sides of the semiconductor substrate. The optical waveguide structure has a reflector and a waveguide body. The optical signal generated from the signal conversion unit sequentially passes the first film, the semiconductor substrate and the second film and enters the optical waveguide structure. Then, the optical signal is reflected by the reflector and transmitted in the waveguide body to be outputted. Alternatively, the optical signal is transmitted in a reverse direction from the optical waveguide structure to the signal conversion unit.