In this paper,microstructure characteristics and phase transitions of Fe-19 wt％Cr-9 wt％Ni nanocrystalline alloy are com-prehensively studied during the mechanical alloying and hot pressing sintering processes.Corrosion resistance of the sin-tered Fe-19 wt％Cr-9 wt％Ni nanocrystalline alloy samples is further analyzed.During the mechanical alloying process,Fe-19 wt％Cr-9 wt％Ni nanocrystalline alloy powders mainly composed of metastable ferrite phase are obtained after mechanical alloying for 8,16 and 24 h,respectively.In the subsequent hot pressing sintering process,the phase transi-tions (from ferrite to austenite) occur from 650 to 750 ℃ for Fe-19 wt％Cr-9 wt％Ni alloy powders milled for 24 h.When the sintering temperature is raised to 1050 ℃ for 1 h,the ferrite phase has transformed into austenite phase completely,and the obtained grain size of sintered Fe-19 wt％Cr-9 wt％Ni alloy is around 40 nm.Electrochemistry test of the sintered Fe-19 wt％Cr-9 wt％Ni alloy has been operated in 0.5 mol L-1 H2SO4 solution to show the corrosion resistance properties.Results show that the sintered Fe-19 wt％Cr-9 wt％Ni alloy exhibits excellent corrosion resistance,which is proved by higher self-corrosion potential,lower self-corrosion current density and larger capacitive reactance,compared with that of com-mercial 304 stainless steel.