The invention relates to submarine observation network equipment, and particularly relates to an underwater photoelectric separating cabin comprising a structural framework, submarine cable force-bearing end heads and a photoelectric separating cabin. The submarine cable force-bearing end heads are installed on the structural framework. Force borne by a submarine cable is borne by the structural framework. Photoelectric composite cables of which steel wire armored sheaths are removed are coiled in the structural framework. The photoelectric separating cabin is installed in the structural framework. The photoelectric composite cables enter into the photoelectric separating cabin via through-wall sealing components, and photoelectric separation is completed via the photoelectric separating cabin. A separated optical channel and an electric channel are led out to lower level equipment to work by the photoelectric separating cabin through the through-wall sealing components. Force borne by the submarine cable is borne by the structural framework so that the underwater photoelectric separating cabin is suitable for the requirements of special equipment, small in size, low in weight, economical in installing space and more suitable for the complex wiring requirements of narrow space.