Abstract: The effects of vanadium(V) micro-alloying on the properties of Z-beam with high strength and weather-resistance were researched according to the mechanical properties tests and precipitated phase analysis for the Z-beam samples prepared under different contents of vanadium and nitrogen by mediumfrequency induction furnace. The results show that V has the effects of refinement and precipitation strengthening in the Z-beam,and addition of nitrogen can enhance the transformation of V from solid solution to precipitation phase increasing the precipitation strengthening of V.It is also evidenced that the finish-rolling temperature is sensitive to the precipitation strengthening of vanadium and nitrogen. A higher precipitated V(C,N) content and yield strength of the Z-beam can be obtained at a lower finish-rolling temperature with the best matching between strength and plasticity of the Z-beam at about 850℃.