During the preparation of amino phosphoric chelating fiber, polypropylene grafted styrene, acetyl, amine series and amino phosphonic acid chelating fibers were certified by infrared spectrum, and the functionalization degree of raw fibers was studied. By the semi-qualitative method of infrared spectrum, the adsorption performance of indium and copper on amino phosphonic chelating fiber was also discussed. The results showed that (1) The peak at 1 116 cm-1 was assigned to —P(ONa)2 in amino phosphonic acid chelating fiber. So the success of phosphorylation was verified. (2) During preparation, the phosphorylation effect of amino phosphonic acid chelating fiber could be reflected by the change of the peaks at 1 056 and 1 110 cm-1. (3) After adsorption of In3+ on amino phosphonic acid chelating fiber, the new forming N-In coordination key was absorbed strongly at the bands of 1 000~1 200 cm-1 and at 1 107, 699 and 617 cm-1. After adsorption Cu2+ on amino phosphonic acid chelating fiber two new strong and wide peaks were found at 1 110 and 618 cm-1, respectively. (4) Through the area change of the bands at 1 200~900 and 600 cm-1 , the adsorption performance of indium and copper on amino phosphonic acid chelating fiber was compared.