The sorption behavior of amino methylene phosphonic acid resin (APAR) for In (Ⅲ ) was investigated . Experimental results show that In ( Ⅲ ) adsorbed on APAR can be elated with 2mol · L -1 HCl. The apparent rate constant is k29 = 1.50 × 10-5s-1. The sorption behavior of APAR for In ( Ⅲ ) obeys the Freundlich isotherm. The themodynamic parameters of sorption, enthalpy change ()H, free energy change ()G and entropy change ()S of sorption (APAR) for In ( Ⅲ ) are 24.1 kJ·mol-1, -35. 1kJ· mol-1 and 200J· mol-1·K-1 respectively. The coordination molar ratio of the functional group of APAR to In( Ⅲ ) is 2:1. The sorption mechanism of APAR for In( Ⅲ ) was examined by IR spectrometry. The sorption behavior of amino methylene phosphonic acid resin (APAR) for In (III) was investigated. Experimental results show that In (III) adsorbed on APAR can be eluted with 2 mol · L -1 HCl. The apparent rate constant is k29 = 1.50 × 10-5s-1. The sorption behavior of APAR for In (Ⅲ) obeys the Freundlich isotherm. Themodynamic parameters of sorption, enthalpy change () H, free energy change () G and entropy change () S of sorption ) for In (III) are 24.1 kJ · mol -1, -35.1 kJ · mol -1 and 200 J · mol -1 · K -1 respectively. The coordination molar ratio of the functional group of APAR to In (III) is 2: 1. The sorption mechanism of APAR for In (III) was examined by IR spectrometry.