A quartz crystal microbalance(QCM) method was developed for the determination of heavy metal ions by using MBA functionalized gold nanoparticles as signal enhancer,and ercaptoethylamine-modified gold electrode with the help of self-assembly monolayer(SAM) techniques.In a typical experiment,cadmium(Ⅱ) bounds with amino-groups on gold electrode through complexation.After that,MBA modified nanoparticles were assembled onto gold electrode through complexation of carboxyl group of gold nanoparticles to cadmium(Ⅱ),thus leading to a mass change which could be used to detect cadmium(Ⅱ).Determinations of lead(Ⅱ),mercury(Ⅱ) and copper(Ⅱ) was also studied using this strategy.The results showed that the methodology has low detection limit,high sensitivity and good reproducibility.