Solar desalination is a promising technique to remedy the worldwide water crisis with minimum environmental impact. Herein, we successfully converted the wood wastes (sawdust) to construct biochar as an evaporator. Plasmonic metal doped the biochar to enhance steam generation (SG) via the multiple nucleation sites, benefiting from their excellent light absorption. As a result, the evaporator achieves an evaporation rate of 0.657 kg m^-2 h^-1 (77.0% efficiency) under 1 sun illumination. The evaporator showed extraordinarily salt-resistant performance under 1 sun illumination to the different interactions of salt ions with the functional groups of biochar. Based on its facile and cost-effective fabrication process, excellent energy-conversion efficiency, salt-resistance, and durability, the prepared evaporator may be a promising generator for freshwater on a large scale.