The invention relates to a device and method for lifting liquid by means of temperature difference of solar energy. The device for lifting liquid by means of the temperature difference of solar energy comprises a heat colleting and temperature uniformizing device, a transparent cover plate, a waterproof sealing layer, a heat insulation layer, a shell and buoys, wherein the heat colleting and temperature uniformizing device is composed of a heat absorption disc, a temperature uniformizing heat exchange bar, a trapezoid straight rib and a rectangular straight rib. In daytime, a heat absorption disc on the upper portion of the heat colleting and temperature uniformizing device converts solar energy into high-temperature heat energy. Part of the heat energy is transmitted into water in a cavity in the lower portion of the heat absorption disc, so that the water is heated and the temperature of the water rises, and the part of heat energy is stored. The other part of heat energy is directly transmitted to the lower end of the device through the temperature uniformizing heat exchange bar and is used for generating upward flow. At night, the high-temperature hot water stored in the sealed cavity in the lower portion of the round disc transmits the collected high-temperature heat energy collected in daytime to the deep seawater at the lower end of the device, so that the deep seawater is heated continuously to generate upward flow. According to the device and method for lifting liquid by means of the temperature difference of solar energy, solar energy is used for driving the upward flow, and environmental friendliness is achieved.