Abstract: In recent years, photothermal-driven desalination has been regarded as one of the most promising methods to solve the global crisis of freshwater scarcity. The solar generation of water vapor (SGWV) is a key process in seawater desalination which uses simple equipment and has a high cost-benefit. Among alternative photothermal conversion materials for a SGWV system, three-dimensional (3D) monolithic carbon-based materials have many advantages, including low cost, good structure control, and high light-harvesting efficiency which gives a high evaporation rate. 3D monolithic carbon-based materials with a high photothermal conversion efficiency are reviewed together with their use in interface SGWV. The working mechanism of SGWV and the classification of SGWV materials are first considered, followed by detailed consideration of 3D monolithic carbon materials, including their design, preparation and working mechanism in SGWV. Finally, both the advantages and disadvantages of 3D monolithic carbon materials with a high photothermal conversion efficiency are examined.