Disclosed are Cu-Nb anti-corrosion reinforced austenitic stainless steel and a preparation method thereof. The Cu-Nb reinforced anti-corrosion austenitic stainless steel is prepared from the alloy elements of less than or equal to 0.07 of C, 8.0-10.0 of Ni, 17.0-19.0 of Cr, less than or equal to 0.54 of Nb, 0.2-0.8 of Cu, less than or equal to 2.0 of Mn, less than or equal to 1.0 of Si, less thanor equal to 0.035 of P, less than or equal to 0.030 of S, and the balance Fe, wherein Nb is greater than or equal to 7.73*(C-0.01) and smaller than or equal to 7.73*C. After alloy smelting, niobium carbide (NbC) is fully crushed and dispersed through thermal deformation cogging and cold deformation, and coarse austenite grains are obtained by high-temperature solution treatment. The alloy corrosion current in an H2SO4 electrolyte with the molar concentration of 0.5 mol/L containing 5*10<-6>F minus at 80 DEG C under hydrogen conditions is 10.8-13.7 [mu]A/cm<2>. Compared with 304L stainless steel, the corrosion rate is greatly reduced while the mechanical property is slightly better than that of the 304L stainless steel.