A fabrication method of the C+N austenitic stainless steel with high mechanical strength and excellent corrosion resistance, which consists of: 8 to 12 wt.% manganese (Mn); 15 to 20 wt.% chromium (Cr); 2 wt.% or less nickel (Ni); 0.6 to 1.0 wt.% of total C+N content, with 0.3 or higher wt.% nitrogen; 4 wt.% or less tungsten; 2 wt.% or less molybdenum (Mo); a balance of iron (Fe); and unavoidable impurities, the fabrication method comprising: master alloy charging in which a master alloy for the stainless steel having the composition of 8 to 12 wt.% manganese (Mn); 15 to 20 wt.% chromium (Cr); 2 wt.% or less nickel (Ni); 0.6 to 1.0 wt.% of total C+N content, with 0.3 or higher wt.% nitrogen; 4 wt.% or less tungsten; 2 wt.% or less molybdenum (Mo); a balance of iron (Fe); and unavoidable impurities is charged into a vacuum melting furnace; vacuum maintaining in which the vacuum melting furnace with the master alloy charged therein is maintained under vacuum; master alloy melting in which the vacuum melting furnace is heated and the master alloy is melted; nitrogen content adjusting in which nitrogen gas is injected into the vacuum melting furnace to make nitrogen content in the C+N austenitic stainless steel as indicated above; melted alloy agitating in which the melted master alloy is agitated; ingot forming in which an ingot is formed by pouring the agitated melted alloy from the vacuum melting furnace; hot-rolling the formed ingot; and performing water quenching of the hot-rolled stainless steel to prevent precipitation of carbide which degrades the mechanical property and corrosion resistance, wherein the nitrogen content adjusting comprises: nitrogen gas injecting in which nitrogen gas is injected to the interior of the vacuum melting furnace; and pressure adjusting in which the partial pressure of nitrogen gas of the interior of the vacuum melting furnace is adjusted to 1 atm. master alloy charging in which a master alloy for the stainless steel having the composition of 8 to 12 wt.% manganese (Mn); 15 to 20 wt.% chromium (Cr); 2 wt.% or less nickel (Ni); 0.6 to 1.0 wt.% of total C+N content, with 0.3 or higher wt.% nitrogen; 4 wt.% or less tungsten; 2 wt.% or less molybdenum (Mo); a balance of iron (Fe); and unavoidable impurities is charged into a vacuum melting furnace; vacuum maintaining in which the vacuum melting furnace with the master alloy charged therein is maintained under vacuum; master alloy melting in which the vacuum melting furnace is heated and the master alloy is melted; nitrogen content adjusting in which nitrogen gas is injected into the vacuum melting furnace to make nitrogen content in the C+N austenitic stainless steel as indicated above; melted alloy agitating in which the melted master alloy is agitated; ingot forming in which an ingot is formed by pouring the agitated melted alloy from the vacuum melting furnace; hot-rolling the formed ingot; and performing water quenching of the hot-rolled stainless steel to prevent precipitation of carbide which degrades the mechanical property and corrosion resistance, nitrogen gas injecting in which nitrogen gas is injected to the interior of the vacuum melting furnace; and pressure adjusting in which the partial pressure of nitrogen gas of the interior of the vacuum melting furnace is adjusted to 1 atm.