Superhydrophobic surfaces are used in aerospace, medical equipment, transportation, household appliances and other fields due to their special interface characteristics. In this paper, a superhydrophobic surface is prepared by Selective Laser Melting (SLM) 3D-printed technology, comparing the effects of different post-treatment methods and time on corrosion resistance, and revealing the root cause of the transition from hydrophilic to superhydrophobic. The test results show that for samples not treated with fluoro-silane, the microstructure adsorbs the organic matter in the air and reduces the surface energy, which is the root cause of the sample surface changing from hydrophilic to superhydrophobic. In addition, the corrosion resistance of 3D-printed, polished, 3D-printed + modified, and 3D-printed + corroded samples are analyzed. Among them, 3D-printed + modified samples have a longer resistance to corrosion, and after placing in outdoor natural conditions for 60 days, the contact angle of water droplets on the surface is 150.8°, which still has superhydrophobic properties and excellent natural durability.