This study investigated the precipitated phases of Titanium-stabilized 15Cr-15Ni austenitic stainless steel with different niobium contents (0-0.46 wt.%), in which the types, morphology and distribution of precipitated phases after solution treatment and aging treatment were characterized by means of OM, SEM, and TEM. Results show that Ti and Mo can be partly replaced with Nb in (Ti,Mo)C phase to form a Nb-rich (Nb,Ti)C phase in 0.21wt.%Nb and 0.46wt.%Nb alloys. What’s more , the increase of Nb content refines austenite matrix structure after solution treatment. In addition , the main phases in the alloy after aging at 850℃ for 1000h are sigma and MC carbides .the increase of Nb content not only promotes to enrich Nb and Mo elements in the sigma phases, but also furthers it to be finer and dispersed. Besides, in the range of 0-0.46wt.%Nb, the tensile results of solution and aged specimens at room temperature and 650℃ show that the increase of Nb content has little effect on the tensile properties of the solution alloy at room temperature and high temperature, while the sigma promoted by Nb has no effect on the tensile properties of the aged alloy.