Titanium alloys have great application prospects in marine engineering due to their excellent corrosion resistance, but the disadvantages such as poor wear resistance and crevice corrosion under severe conditions also affect their application. The work summarized the conditions and causes of crevice corrosion of titanium alloys and the effects of normal plasma nitriding on their wear resistance and corrosion resistance and mainly discussed the effects of surface nanocrystallization on corrosion resistance and adhesion of plasma nitriding of titanium alloys. It was found that the crevice corrosion of titanium alloys occurred in a harsh environment of high temperature (above 65 ℃), high acidity (low pH), high Cl- concentration and low oxygen concentration. Oxygen concentration cell and self-catalytic acidification were the main mechanisms for the crevice corrosion of titanium alloys, and the formation of brittle TiH2 by hydrogen absorption accelerated the process of crevice corrosion. The TiN and Ti2N layers with high hardness formed by normal plasma nitriding on the surface of titanium alloys could improve their wear resistance and uniform corrosion resistance. However, the large hardness difference between nitriding layer and titanium matrix lead to a weak bonding force, and the nitriding layer was easy to exfoliate during corrosion process. The surface gradient nanocrystalline structure prepared by surface nanocrystallization technology is expected to obtain nitrided layer structure with good binding force through plasma nitriding and can effectively reduce nitriding temperature.