A seawater desalination device including: a seawater introducing and filtering device, a seawater reverse osmosis filtering device, and a control circuit. The seawater reverse osmosis filtering device includes a first control valve and a second control valve. The seawater introducing and filtering device is connected to the first control valve of the seawater reverse osmosis filtering device. The second control valve is disposed at a terminal pipe of the seawater reverse osmosis filtering device. The control circuit is adapted to control operations of the seawater reverse osmosis filtering device.