Super duplex stainless steel has along life in severe environments because of its strength and corrosion resistance. If 0.2$sim$0.3% Nitrogen in aninterstitial solid solution is added, the austenite structure is reinforced. This improves the solid solution hardening and the anticorrosionability. In this study, the mechanical properties and structures of the super duplex stainless steel with the 0.2% N additive were investigated to determine the effect of various volume fractions on the austenite phase. The various volume fractions and distributions of the austenite structure in the applied test specimens were obtained by changing the heat treatment temperature and cycle. The characteristics by amounts of the $sigma$ phase obtained from the precipitation heat treatment were alsoinvestigated. From the results, when the austenite volume fraction increases, the tensile strength decreases and elongation increases. And the $sigma$ phase was rapidly increased by increasing the heat treatment time. When the volume fraction of the $sigma$ phase increased, tensile strength increased.