• A three-dimensional multiscale liquid metal/polyacrylonitrile (LM/PAN) evaporator is fabricated via wet spinning and assembly, inspired by the hierarchical stem structure of the bird of paradise.
• The evaporator achieves an outstanding water evaporation rate of 2.66 kg m−2 h−1 with a solar energy efficiency of 96.5% under one sun irradiation, and 2.58 kg m−2 h−1 in brine.
• The evaporator demonstrates superior purification performance for seawater, reducing Na+, Mg2+, K+, and Ca2+ concentrations by three orders of magnitude to less than 7 mg L−1 after desalination.
• The hierarchical structure of the LM/PAN evaporator optimizes water transportation and thermal management, offering valuable design principles for advanced solar steam generation systems.