Based on a mass balance equation, in this paper, the kinetic model of chromatography including influence of the radial diffusion on the mass transfer process is set up. Based on the hypothesis of Giddings, this model has been simplified. In this way, the expressions of the first moment, the second and the third central moment for this model are derived by Laplace transform in detail. The results show the radial diffusion affects not only the column efficiency, the peak spreading and the peak symmetry, but also the retention time.