A facile approach to fabricate sustainable and largescale polydopamine (PDA) and silver nanoparticle (AgNP)-coated cotton fabrics (P-Ag-P@CFs) as photothermal solar evaporators for efficient interfacial solar steam generation was proposed. The P-Ag-P@CFs were facilely fabricated in a large scale (2.3 m × 1.0 m) by coating PDA and AgNPs on cheap and green cotton fabrics via the self-polymerization of dopamine through a dip-coating combined with oven drying method and in situ reduction of Ag + by dopamine, respectively. Thanks to the synergistic effect of PDA and AgNPs, the P-Ag-P@CFs show remarkable light absorption and solar-tovapor efficiency (over 90% for deionized water under 1-sun irradiation), resulting in a high evaporation rate of 1.378 kg m −2 h −1 . Moreover, the P-Ag-P@CFs display an excellent purification efficiency and degree for several kinds of aqueous solutions, such as seawater, simulated sewage, and industrial wastewater. The desalinated water is compliant with the standards of drinking water.