Abstract: Study on the effects of different kinds of interstock on the annual changes in the contents of 8 kinds of mineral nutrient in root by doing field experiment with the materials “Newhall navel orange/3 kinds of interstock/trifoliate”. The results indicted the following. 3 kinds of interstock had no obvious effects on the tendencies of the annual changes in the contents of 4 kinds of mineral nutrient such as P and K and Mg and Fe in root, and had noted effects on annual changes in the contents of N and Ca and Mn and Zn in root. The contents of K and Ca and Mn in root among 3 kinds of interstock had remarkable difference during every period of the annum. The contents of the other kinds of mineral nutrient among 3 kinds of interstock had remarkable difference during some periods of the annum. Meanwhile, among the periods when the contents of each mineral nutrient had significant difference, the tendency of the relative difference of the kind of mineral nutrient in one period didn’t always have the same turn as the others.