Freshwater resources are the most precious resources for human survival. Although 71% of the area on the earth is covered by water, freshwater resources account for less than 3% of them, and 87% of them are difficult to obtain. Therefore, among the freshwater resources that people can control, we should not only save water but also have the idea of open source, which is of key significance to the history of human civilization. At present, the open source of human research is mainly sewage purification and seawater desalination, but whether sewage purification or seawater desalination, the traditional scale requires complex processes, high equipment costs and a large amount of fossil energy consumption. therefore, the choice of clean energy is more in line with the green strategic policy of human development. As a globally distributed renewable resource, solar energy has been effectively used in many fields, such as plant photosynthesis, photovoltaic cells, photochemical reaction and photothermal effect. At present, many solar photothermal converters are used in the production of fresh water, including wastewater purification, sterilization and desalination. But most materials are difficult to maintain high efficiency or water evaporation for a long time, and still need to be improved to a great extent. Therefore, the next research goal is to improve the evaporation effect of the evaporator to water, the removal of impurities in sewage and the filtration of seawater ions.