Abstract: Solar interface water evaporation technology has a broad application prospect in solving the shortage of energy and fresh water resources that mankind is currently facing. Water transport was a very important step in the solar steam generation process. The ideal water transport was to transport the right amount of water to maintain efficient and stable water evaporation from the solar evaporation layer. The capillary force generated by the porous structure of the evaporation layer determined its ability when transporting water. Therefore, the pore structure inside the evaporation layer was very important. In this paper, a porous carbon nanotubes-hydroxyethyl cellulose/polyvinylidene fluoride (CNTs-HEC/PVDF) composite membrane for solar interfacial water evaporation was produced, which was doped with HEC and cross-linking with glutaraldehyde on a PVDF depended on the excellent light absorption capacity of CNTs. The solar interfacial water evaporation performance was improved as the microchannels formed by the porous structure of CNTs-HEC/PVDF composite membranes enhanced water transport and vapor escape. The water evaporation rate reaches 1.81 kg·m⁻²·h⁻¹ under 1 kW·m⁻² of solar irradiation, and the corresponding photothermal conversion efficiency is 95%. The relevant experimental results also show that the composite membrane has excellent recycling performance, chemical stability and efficient sewage purification ability.