NOVELTY - The device comprises an impounding reservoir provided with a water inlet pipe and a water outlet pipe, a transmission box provided with two groups of input end of the driving gear and a group of input end of the driven gear, a gear box (611), a high pressure pump (619), a reverse osmosis membrane assembly (620), a booster pump, turbines, a generator, a storage battery and an electric motor. The water inlet pipe and water outlet pipe are respectively provided with a first electromagnetic valve and a second electromagnetic valve. A first water turbine (603) is placed on the water inlet pipe.    USE - The device is useful for desalting sea water and generating the power.    ADVANTAGE - The economical device is capable of desalting the sea water with less renewable energy source and generating power with high electric energy.    DETAILED DESCRIPTION - The device comprises an impounding reservoir provided with a water inlet pipe and a water outlet pipe, a transmission box provided with two groups of input end of the driving gear and a group of input end of the driven gear, a gear box (611), a high pressure pump (619), a reverse osmosis membrane assembly (620), a booster pump, turbines, a generator, a storage battery and an electric motor. The water inlet pipe and the water outlet pipe are respectively provided with a first electromagnetic valve and a second electromagnetic valve. A first water turbine (603) is placed on the water inlet pipe present in the water storage tank. A second water turbine (604) is disposed on the water outlet pipe of the water storage tank. The input end of the driven gear is respectively connected with the group of input end of the driving gear or separated from the input end of the driving gear that are respectively provided with a power input shaft. The power input shaft is connected with a power output shaft of the water turbine, an other power input shaft and the power output shaft of the second turbine. A power input shaft of the gear box is connected with the power output shaft of the transmission box. The high pressure pump is connected with the water inlet and the sea water. The power input shaft is connected with the power output shaft of the gear box. The reverse osmosis membrane assembly is provided with a fresh water outlet and a concentrated sea water outlet. The water inlet of the reverse osmosis membrane assembly through a first one-way valve is connected with the high pressure pump connected with the water inlet. The booster pump is connected with the water inlet through a second one-way valve connected with the first one-way valve. The high pressure pump outlet is connected with the valve and the reverse osmosis membrane assembly. A connecting pipe is connected with the first signal of the booster pump connected with the turbine. A power input shaft of the generator is connected with the power output shaft of the turbine. The storage battery provides power source for electric generator. The working power is supplied by the storage battery. The power output shaft of the motor is connected with the power input shaft of the booster pump.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a sea water desalting and power generating device.    First turbine (603)    Second turbine (604)    Gear box (611)    Reverse osmosis membrane assembly (618)    High pressure pump. (619)