The invention provides a floatable free-moving seawater evaporation collection device utilizing solar energy, which realizes solar-to-heat conversion to obtain a high-efficiency photothermal conversion rate based on an interfacial solar-to-heat conversion principle. The device includes a condensing light transmission module, a mounting and holding module, a fresh water collection module, a balancemodule, and the like. The top of a device tank body is connected to the light transmission module. The light transmission module is connected to the bottom mounting and holding module through a connecting bar. The top of the light transmission module is provided with a photosensitive sensor through which a hydraulic cylinder on the mounting and holding module is controlled to achieve adjustment of solar light intensity. The mounting and holding module is connected to the inner side of the tank body through hydraulic cylinders. The fresh water collection module is mounted around the tank body.The outer side of the tank body is connected to the balance module through hydraulic cylinders. Solar panels are installed around the tank body. The device has the advantages of a simple structure, alow cost, convenient operation, green materials, capability of floating on the sea surface without maintenance with special persons, no need of salt stain cleaning, and transient-state adjustment oflight intensity along with solar motion.