Abstract: The microstructure and corrosion resistance of AUS-10 stainless steel were studied by optical microscopy（OM）, scanning electron microscopy（SEM）, electron probe microanalysis（EPMA）, energy dispersive spectrometer（EDS） and hardness test. The reasons for the corrosion failure of the kitchen knife made of AUS-10 martensitic stainless steel were studied. The results show that, despite from the point of microstructure and hardness, the heat treatment process for AUS-10 is correct, but there are a lot of coarse carbides in the original structure, which can cause local lean chromium and then leading to pitting corrosion. Thus, AUS-10 with low Cr content is recommended for the application with low corrosion requirements.