An ion-exchange terpolymer resin was synthesized from acrylic acid-maleic anhydride-vinyl acetate. The resin was characterized by FTIR. The thermal analysis (TGA) was performed at the heating rate of 20ºC/min in N2 atmosphere. The ion-exchange property of the terpolymer showed a powerful adsorption towards specific metal ions like Cu2+, Fe2+, Ni2+ and Co2+. A batch equilibration method was adopted to study the selectivity of the metal ion between the resin and a solution containing the metal ion. The effect of external stimuli, such as the solution pH, ionic strength, resin quantity, contact time and temperature was investigated.