A static corrosion experiment of 347H stainless steel alloyed with elements Cu and Mo was carried out in a nitrate molten salt (60% NaNO₃+40% KNO₃) at 565 °C for 720 h. The effects of elements Cu and Mo on the corrosion resistance of 347H stainless steel in molten salt were investigated by analyzing the phase composition, microstructure and chemical composition of the corrosion products. The results show that the grain refinement induced by element Mo imparts the stainless steel with optimal corrosion resistance at a medium grain size. Furthermore, the formation of MoC significantly enhances the intergranular corrosion resistance of the stainless steel. The stainless steel exhibits uniform corrosion in the nitrate solution. The corrosion layer displays a dual-layer structure, and the corrosion products protecting matrix are present in both the inner and outer layers. The outer layer consists of a mixture of Fe oxides (Fe₂O₃, Fe₃O₄), NaFeO₂, and a minor amount of MgFe₂O₄. Conversely, the inner layer is primarily composed of a spinel layer (FeCr₂O₄, MgCr₂O₄) and a thin Cu₂O layer. The oxidation of Cu in the inner layer leads to the formation of a dense Cu₂O layer, effectively impeding O^2- plasma infiltration into the matrix.