Solar water evaporation assisted by photothermal membranes is considered to be one of the sustainable and cost-effective strategies for pure water generation and wastewater treatment. In this work, a self-assembled reduced graphene oxide (rGO) film has been prepared and proposed for direct solar thermal desalination. The morphology, structure, absorbance and desalination performance of the rGO film are explored. It is found that rGO film with optimized microstructure delivers an evaporation rate of 0.87 kg m−2 h−1 with solar thermal conversion efficiency of 46% under 1 sun illumination. Moreover, the evaporation rate of rGO film remains at 0.86 kg/m2·h−1 after ten times recycling, demonstrating the superior reusability.