Sm(III) was quantitatively adsorbed by amino methylene phosphonic acid resin (APAR) in the medium of pH=5.0. The statically saturated sorption capacity is 251mg/g·resin. Sm(III) adsorbed on APAR can be reductively eluted by 2.0mol/L HCl. The sorption rate constant is k298= 1.35×10-5s-1. The sorption behavior of APAR for Sm(III) obeys the Freundlich isotherm. The enthalpy change △H of sorption is 24.9kJ/mol. The apparent activation energy is Ea=11.7kJ/mol. The sorption mechanism shows that the nitrogen and oxygen atoms of the functional group of APAR coordinated with Sm(III) to form coordination bond. Sm (III) was quantitatively adsorbed on the amino methylene phosphonic acid resin (APAR) in the medium of pH = 5.0. The statically saturated sorption capacity is 251 mg / g · resin. / L HCl. The sorption rate constant is k298 = 1.35 × 10 -5 s -1. The sorption behavior of APAR for Sm (III) obeys the Freundlich isotherm. The enthalpy change ΔH of sorption is 24.9 kJ / mol. The apparent activation energy is Ea = 11.7 kJ / mol. The sorption mechanism shows that the nitrogen and oxygen atoms of the functional group of APAR coordinated with Sm (III) to form coordination bond.