In order to identify the affect of vanadium in pearlite transformation and the regularity of the precipitation, the effect of vanadium content on VC precipitation in PD3 steel has been studied by electrochemical extraction and TEM. The results show that the solid solubility limit of vanadium in the ferrite and Fe 3C is 0.09% and 0.23% respectively, that vanadium exist mainly as solid solution and a few VC particles are precipitated in disordered way in case of the vanadium content being below 0.21%, that VC particles are precipitated in excess of saturated solubility, and that a lot of VC particles are precipitated in disordered and "interphase precipitated" way in case of the vanadium content being above 0.21% and arrive at 0.33%.