The basic structure of classical Wolter type I grazing incidence optical system was presented. And a set of equations, through which the main basic parameters of a grazing incidence optical system were calculated, were calculated from the common equations of those reflecting surfaces. In addition, it was discussed that how to evaluate and optimize the classical Wolter type I grazing incidence optical system using optical design code Zemax’s macro language. And specific optimized example was discussed. A hyperboloid-hyperboloid grazing incidence optical system with the same aperture and focal length is achieved from the classical paraboloid-hyperboloid Wolter type I. And the evaluation results of those two grazing incidence optical system show that the optical system’s resolution for wide-field has significant improvement and it could meet top-resolution full-disk solar observation requirement.<收到修改稿日期李顺>2008-12-02