The effect of Ta, Nb, Hf and Zr on the microstructure and high temperature tensile properties of DM02 alloy, which is a novel developed Ni base superalloy for high temperature die material, had been studied in this paper. The results showed that the four alloying elements affect the composition and morphology of carbides obviously, and have almost no effect on the morphology and size of γ´ phase in DM02 alloy. 0.5-1wt% Hf make the morphology of MC carbide change from bone-like to blocky and inhibit the formation of primary M6C carbide, thus improve the ductility of DM02 alloy, while 0.1wt% Zr has no similar effect. The strengthening effect of 3wt% Ta is better than that of 1.5wt% Nb. DM02 alloy with 3wt% Ta and 0.5wt% Hf has high strength and good ductility at 1050°C.