Abstract: The fretting corrosion wear behavior and mechanism of 316L stainless steel in saline solution have been investigated with a fretting test rig in a ball on disc contact configuration. The worn surface morphologies and corrosion wear mechanisms have been examined by means of scanning electron microscopy. As the results, the fretting process can be divided into four stages. Namely, stage 1 refers to the initial or running in stage where the worn steel surface is characteristic of slight wear, though the wear rate rises considerably with increase of fretting cycle in this stage. Stage 2 refers to the first steady stage where the fretted surface of the stainless steel shows signs of severe plastic and elastic deformation, and a high friction coefficient is recorded. The signs of crevice corrosion are also observed in the first steady stage, due to the mechanical damage and closed fretted area. With the increase in the fretting cycle, both the mechanical damage and crevice corrosion effects accumulate. Then it comes to stages 3 and 4, the second transitional and steady stages where the fretting damage is largely attributed to micro crack and corrosion fatigue. Moreover, there exists some correlation among the friction coefficient variation and the fretting damage rate and fretting mechanisms.