Solar‐driven steam generation membranes have garnered increasing attention for freshwater production. Nonetheless, the adverse impact of salt accumulation on membrane surfaces directly undermines the efficacy of solar evaporation. In this work, one type of composite membrane comprised of carbon nanotubes (CNTs)‐styrene‐ethylene‐butadiene‐styrene (SEBS) was fabricated by modified vapor phase pore‐forming technique. Through the grafting of maleic anhydride (MAH), the CNTs‐SEBS‐MAH composite membrane was successfully hydrolyzed. As a consequence, the composite membrane exhibits evaporation rate as high as 1.28 kg m−2 h−1 under one sun solar irradiation, accompanied by an outstanding solar vapor conversion efficiency of 87.5%. In addition, the fabricated composite membrane has high resistance to salt accumulation, as well as self‐cleaning capability. This work provides a route for manufacturing hydrophilic polymer composite membrane towards solar energy driven seawater desalination.