Abstract: The effect of rotation the structure and evolution can be divided into two sections，namely，the dynamical effect and rotational mixing.We have investigated the effect of rotation on the thermal structure of 20 M⊙，adopting the MESA code.The dynamical effect decreases the central temperature，surface opacity，mean molecular weight，and surface entropy.The dynamical effect of rotation can adjust the thermal structure and make the nuclear generation rate lower and cause the star to shift towards lower temperature and luminosity.The rotational mixing can reduce the central temperature，pressure，density，average molecular weight，surface opacity，and central compactness.The chemical elements，such as He，N can be enhanced due to rotational mixing.The region of the nuclear generation can be enlarged and the life span of the star can be extended.

Key words: stellar structure and evolution, rotation, mixing of chemical elements