The present paper deals firstly with the indexes of activation of iron oxides in soil on the basis of the data from previous paper and reference literatures.It is considered that the change of activity of iron oxides in soil.may be summarized as activation and aging.Though the change is not a reversible reaction,the aged iron oxides can be activated by the ac lion of organic matter and atmospheric factor.It is also o}nsidered that mineralogical patterns can not reflect quantitatively the change of activity of iron oxides;however,it can be estimated quantitatively to a certain degree by the content of amorphous iron oxides.