Abstract: Three diffusion coefficients which can affect the diffusion process are calculated. The effects of the chemical elements mixing are given according to the diffusion equation of the chemical elements. It is shown that meridional circulation is the main driving mechanism for the transport of angular momentum while shear turbulence is the main driving mechanism for the transport of chemical elements. The larger horizontal turbulence tends to in- crease diffusion efficiency of meridional circulation and shear turbulence. The diffusion effect favours the transporta- tion of helium and nitrogen to the surface of rotating stars and a large convective core. The diffusion of the chemical element can make the star to have a higher luminosities and a lower temperature in the center of the star and have an important effect on the structure and evolutinn of the star.

Key words: stellar structure and evolution, rotation, chemical elements diffusion