Abstract: The hot corrosion behavior of 316L stainless steel coated with NaCl salt film at 650 ℃and 750 ℃was studied in air atmosphere,and the corrosion products and specific corrosion mechanism at different time points were studied. In the experiment,the weight gain method was used to draw the hot corrosion kinetic curve,and XRD,SEM and EDS were used to characterize the phase,surface morphology,cross-section morphology and cross-section element distribution of hot corrosion products at different time points. The results show that hot corrosion is the result of high-temperature oxidation and chlorination,and its corrosion rate is rapid at first and then slow. The bonding between the corrosion layer and the metal matrix is poor,and there is delamination. The outer layer is loose and consists of a large amount of Fe oxide and a small amount of Cr oxide,while the middle layer is dense and consists of Fe,Cr oxide and a small amount of spinel oxide. The corrosion affected zone on the metal matrix is a porous and cracked Cr-poor zone.