Abstract: In this dissertation,the complexation between glycine and ferrous ions was studied by UV - Vis spectroscopy .The influences of complexation, such as temperature, ionic strength, coordination and pH value were observed. The result shows that: the ionic strength I = 0.02;the complex rate of glycine and ferrous ions (Gly / Fe) is 4:1; pH = 5.0,the rate constant of the complexation had the largest separately.It wsa accounted that the Activation energy Ea was 4291.35J/mol by the equation of Arrhenius, and free energy △G≠ was 1786.60J/mol by the equation of Absolute-rate theory,and the temperature was not affect the the formation rate obviously. the complexation between glycine and ferrous ions was second-order reaction when glycine excess and ferrous ions excess. In the end,The theoretical basis was provided for the preparation of high purity ferrous glycine.