Abstract: Aiming at the problem about the lack of freshwater, a new tubular solar desalination unit is developed and its performance is tested in this research. Under the conditions of constant power and temperature, tests were implemented to measure the quantity of water yield per hour and the temperature at measuring points. Experimental results shown that, compared with traditional desalination device, the performance was greatly improved. The maximum performance ratio of the unit could reach to 1.5, and the maximum water production reach to 20.078 kg/(m²·d) . The higher of the operating temperature, the more yield of freshwater. Moreover, in the same experimental conditions, two-stage device could get higher water yield than that from one-stage device.