The cylindrical rough structure was etched on the surface of 6061 aluminum alloy by microsecond laser with different power densities, and the etched rough aluminum alloy sheet was kept in a drying oven at 110 ℃ for 12 hours. The surface rough structures, and the changes of the wettability, surface element, group, and crystal structure before and after heat treatment were characterized by droplet shape analyzer, scanning electron microscope, optical profiler, and X-ray photoelectron spectroscopy. Experimental results show that the rough aluminum alloy surface etched by microsecond laser has a micro/nano composite structure, and the amount of hydroxyl (—OH) on the surface is reduced after heat treatment. The non-polar component (C—C(H)) is the main component of organics adsorbed on the aluminum alloy surface, and the heat treatment accelerates the adsorption process, which changes the wettability of the rough aluminum alloy surface from the superhydrophilic surface to the superhydrophobic surface.