NOVELTY - The reverse osmosis sea water desalination system comprises a power device, a recycling device, a reverse osmosis membrane, and a water inlet pipe. The power device is connected with the water inlet pipe. The power device and water inlet pipe are connected with the energy recycling device. The reverse osmosis membrane is connected with the energy recovery device. The energy recovery device comprises a first piston, a hydraulic pressure cylinder, a draining valve, and a recycle valve. The piston is installed on the hydraulic cylinder, and is connected with the power device.    USE - Used as a reverse osmosis sea water desalination system.    ADVANTAGE - The reverse osmosis system allows desalination of the sea water in an energy efficient manner.    DETAILED DESCRIPTION - The reverse osmosis sea water desalination system comprises a power device, a recycling device, a reverse osmosis membrane, and a water inlet pipe. The power device is connected with the water inlet pipe. The power device and water inlet pipe are connected with the energy recycling device. The reverse osmosis membrane is connected with the recycling device. The recycling device comprises a first piston, a hydraulic pressure cylinder, a draining valve, and a recycle valve. The piston is installed on the hydraulic cylinder, and is connected with the power device. The hydraulic pressure cylinder includes a raw material sea water inlet and a concentrated sea water outlet. The draining valve is connected with the raw material sea water inlet and a waste concentrated water outlet. The recycling valve is connected with the water inlet pipe. The power device comprises a driving motor, a crank, a connecting rod, and a third piston connected with the connecting rod. The drive motor is connected with the crank. The drainage valve includes a water supply channel and discharge channel. The water outlet is connected with the water inlet pipe. The water supply channel is connected to the concentrated sea water outlet of the water pressure cylinder. The discharge channel is connected with the waste concentrated water discharge port. The recycling valve includes a feeding channel and energy exchange channel, a water inlet channel connected with the waste concentrated water outlet, a water outlet channel connected with the raw material sea water inlet. The water supply channel is provided with a water supply valve core, and drainage valve includes a drain valve core. A switch includes a switching valve core, and the recycling valve includes a recycling valve core to realize synchronous opening and closing. The water supply valve core is greater than the drain valve core. The drain valve core is greater than the switch valve core. The recycling valve includes an elastic connecting piece and a recycle valve body. The elastic connecting piece is tightly pressed in a passage port of the valve body when water flow passes through the elastic connecting piece. The water flow passes through the valve cores with a pressure differential across the channel to close or open. A hydraulic pressure is higher in hydraulic cylinder, and is lower in pressure another hydraulic cylinder.