Abstract: For austenitic stainless steel, salt bath carburizing, plasma carburizing and other carburizing processes at low temperature could improve their hardness, but also would reduce their corrosion resistant. In order to solve this problem, on the basis of low temperature colossal supersaturation (LTCSS) process, a kind of gas carburizing process at low temperature was presented, the process could make the stainless steel owning good hardness and corrosion resistance at the same time. Then, 304 and 316 stainless steels were carburized by the technology at 470, 500 ℃,respectively, and the microstructure and properties of the carburized layer were studied. The results show that corrosion resistant strengthened layers with 15-20 μm thickness were obtained on 304 and 316 stainless steels surface after they were carburized at 470 ℃, thier hardness increased by 4-5 times without any lowering of corrosion resistance. The thickness, hardness and corrosion resistance of carburized layer of 316 stainless steel were not better than that of 316 stainless steel.