A passive wavelength division mobile fronthaul network system includes a central office end, a remote end, a trunk optical fiber; a first transport unit, configured to transport, on one end of the trunk optical fiber, detection light to the trunk optical fiber; a second transport unit, configured to transport, on the other end of the trunk optical fiber, the detection light from the trunk optical fiber to each branch of the remote end; and a reflector, deployed on an end of each branch of the remote end for reflecting the detection light. The first transport unit combines the detection light to the trunk optical fiber, the second transport unit transmits, on the remote end, the detection light from the trunk optical fiber to each branch of the remote end, and finally, the reflector returns the detection light along the original path.