The utility model relates to a deepwater ocean water flow velocity measuring system, which comprises a counterweight cage (1), a deepwater underwater acoustic Doppler flow velocity detector (2), a shallow water underwater acoustic flow velocity detector (3), a steel wire rope (4), an electric hydraulic winch (5), an underwater cable (6), an underwater cable junction box (7) and a monitoring workstation (8). Wherein a deep water underwater acoustic Doppler flow velocity detector (2) and a shallow water underwater acoustic flow velocity detector (3) are arranged in the counterweight cage (1); and the deepwater underwater acoustic Doppler flow velocity detector (2) is arranged below the shallow water underwater acoustic flow velocity detector (3). And the counterweight cage (1) is connected with the electric hydraulic winch (5) through the steel wire rope (4). And the two steel wire ropes are connected with the counterweight cage (1). According to the utility model, the real-time monitoring of the water flow speed from the water surface (0 meter) to the underwater 1000 meters, the real-time acquisition of the water flow speed from the underwater 1000 meters to the underwater 2400 meters, and the staged reading and analysis are realized. The device has the advantages of large measurement depth, high automation degree, safety, reliability and flexible adjustment of the measurement depth.