Abstract: Random differential equations of minor noise were established by means of perturbation theory of minor noise. And using perturbation moment theory, the means and variances of random differential equations for material point shift were gotten. At last, the convection-dispersion equations were approximately normalized and the approximate solutions of the equations were gotten. Also the perturbation theory of minor noise was used for solving high convection-dispersion equations and the calculated results were compared with those gotten by generality d ifference format.

Key words: convection-dispersion equation, random differential equation, minor noise, perturbation moment