A kind of casting triple-phase stainless steel(CTSS) containing ferrite, martensite and austenite was obtained by alloy composition design. Thermo-Calc software was used to simulate the microstructure transformation during equilibrium solidification and the effect of solution temperature on austenite stability. Koistinen-marburger (K-M) equation was used to calculate the residual austenite content after solution at 1 050 ℃, which is close to the actual measured results. The results show that after aging treatment, the yield strength, tensile strength and Rockwell hardness of the specimens under the combined action of Laves precipitate and TIRP effect can be significantly increased, while the elongation almost remains unchanged.