Abstract: Photothermal porous materials are the key to solar desalination applications. Inspired by the natural porous interconnected structure of biomass, a carbon-based evaporator with a 3D interconnected pore structure was prepared by freeze-drying and high-temperature carbonization processes, and the microstructural features, water transport and evaporation properties, as well as the enhancement of the material's evaporation performance by the 3D structure, were investigated. The results showed that the evaporator had a highly interconnected pore structure with the optical absorption of 95.5% and achieved an evaporation rate of 1.71 kg/(m²·h) and a photo-thermal conversion efficiency of 89% under one solar, which can effectively evaporate and desalinate seawater. In addition, an evaporation rate of 2.65 kg/(m²·h) was realized under 3D structural features, and the 3D structure effectively enhanced the evaporation performance of the material, showing excellent solar evaporation/desalination effects.