The invention discloses a seawater power generating system. The seawater power generating system specifically comprises turbine machine blades (1) and a driving shaft, wherein the driving shaft is connected to a speed changing box (2), the speed changing box (2) drives a double-pipe hydraulic pump (3), a double-pipe hydraulic pump connecting hydraulic pipe (4) is connected to an energy accumulator (5), the energy accumulator (5) is also connected to a hydraulic motor (6), the hydraulic motor (6) is connected to an electric ball (7), the electric ball (7) is connected with a transformer substation, a double-pipe hydraulic pump (3) is further arranged between the speed changing box and hydraulic pipes, the speed changing box drives hydraulic oil or water of the double-pipe hydraulic pump (3) and presses the hydraulic oil or water into the energy accumulator (5) through the hydraulic pipes (4), the energy accumulator is also connected with a hydraulic motor (6) through the a hydraulic pipe to reach more than 100 kilograms of power generating pressure, and the hydraulic motor (6) drives the electric ball (7) to rotate and generate power and transmits the power to the transformer substation for transformer voltage transformation networking.