Abstract: If dynamic machine foundation is very large, the computation result of the sinplified method recommended in the Dynamic Machine Foundation Design Code(GB50040-96) maybe is error, and which is without avail for the engineering design. So three-dimensional numerical simulation analysis of such foundation is very necessary when we face it in the engineering design. Elasticity dynamic analysis method theory is brief introduced at the beginning of this article. Then dynalic analysis of a dynamic machine foundation has been done by the universal finite element program ANSYS8.0, including two aspects:modal analysis and harmonic response analysis. And then the natural frequency exact computation value of the dynamle frequency is also put out. Ac-cording to the above computation results, some important conclusions are drawn out, which are very useful for the design of correlative engineering.