A new Schiff base compound derived from 1，2，4 triazole was synthesized with a high yield.Potentiometric responses of poly（vinyl） chloride（PVC） electrode based on this ligand as neutral ionophore showed high sensitivity and selectivity towards Hg2+ ion.Effects of different plasticizers and amounts of ion exchanger on the potentiometric response property of Hg2+ selective electrode（Hg2+-ISE） were discussed.The result indicated that，under the optimal membrane composition ［PVC：3270，o NPOE：6539，ionphore：099，ion exchanger：092，（w∶w）］，a good Nernstian response slope of (293±03) mV/dec was obtained for Hg2+ in a wide concentration range of 10×10-6-30×10-4 mol/L with a detection limit of 26×10-7 mol/L Except for silver ion，most of alkali metal，alkaline earth metal and other common transition metal ions didnt interfere the performance of the membrane electrode.The fabricated Hg2+-ISE can be used in a wide pH range of 28-56 with a fast response time of less than 12 s and can be used for 3 month without any obvious change in potentiometric response.The proposed electrode was also successfully applied as indicator electrode in the potentiometric detection of Hg2+ in lab water by standard addition method and the results were confirmed by ICP-MS.