The microstructure, mechanical properties, tensile fractures and the precipitation of the second phase of vanadium microalloyed wire rods with different nitrogen contents are studied by hydraulic universal testing machine, scanning electron microscopy(SEM) and transmission electron microscopy(TEM) . The results show that the interlamellar spacing of pearlite is smaller in high nitrogen steel; the high nitrogen steel has higher yield strength, tensile strength and lower elongation and reduction of area; there are more inclusions on the tensile fracture surfaces of the high nitrogen steel; and in high nitrogen steel, the size of precipitation, mainly precipitating at dislocation or the boundary of austenite, is finer than that of low nitrogen steel, what is more, fine V(C,N) particles are concluded in the precipitations.