PAO(polyacylamidoxime) as chelating adsorbent was synthesized by the amidoximation of polyacrylonitrile with hydroxylalmine. Chemical structure and composition of PAO were identified by infrared spectra and elemental analysis, and specific surface area and density of PAO were also determined. The reaction rate of PAO synthesis and the activation energy were obtained, and the adsorption of copper, cadmium, nickel and zinc with synthesized PAO was discussed. It was found that the synthetic reaction was the first order reaction with respect to the concentrations of hydroxylamine and polyacrylonitrile, respectively. The metal adsorption with PAO was chemical adsorption obeying the Langmuir isotherm, and the amount of adsorbed metals was increased with increasing adsorption temperature and pH of metal aqueous solution. The adsorption selectivity of copper from cadmium, nickel and zinc mixed solution was comparatively high.