A new solid-state mercury ion-selective electrode was prepared by directly coating the surface of a glassy carbon electrode with tetrahydrofuran solution containing PVC, 25,27-dihydroxy-26,28- bis[(1′-naphthalene) selenopropoxy] calix[4]arene, dioctyl phthalate and potassium tetrakis(4-chlorophenyl) borate. The response of the electrode is linear with a good Nernstian slope of 31.5 mV/decade over an Hg 2+ ion concentration range of 5.0×10 -9—5.0×10 -2 mol/L and a detection limit of 1.0×10 -9 mol/L. The response time to achieve a 95% steady potential for Hg 2+ detection is less than 30 s, and the electrode is suitable for use within the pH range of 2—4. The selectivity for Hg 2+ relative to several alkali, alkaline earth, transition and heavy metal ions is good. The mechanism of the potential response of this system was also discussed.