The work aims to investigate the surface behavior of 316L stainless steel (316L SS) implanted in the body at the preliminary stage. The surface morphology, wettability and corrosion resistance of 316L SS in simulated body solution based on immersion test were characterized. The results of white light interference test showed that surface roughness increased with increasing immersion time. A large amount of irregular corrosion pits were found on the surface of 316L SS after immersion for 1 day. Metal ions were released in the corrosion pits. Wettability test results showed that, with prolonged immersion time, the contact angle of 316L SS decreased, while the hydrophily improved and surface energy increased. The electrochemical test indicated that self-corrosion current of 316L SS after immersion for 1 week was threes times the amount of the one before immersion. The corrosion rate increased and corrosion resistance became worse. Local corrosion on the surface of 316L SS occurs in simulated body solution. The surface morphology, composition, wettability and corrosion resistance of 316L SS are changed.