Abstract: In the applications of satellite and ground antenna,the reflectors of an elliptical aperture are often used.Compared with other methods,the Fourier-Bessel method is of the advantages of fast calculation,simple math format,easy understanding and application.Based on the PO and circular aperture,a Fourier-Bessel method was developed to calculate and analyze the radiation fields of parabolic and shaped reflectors.Compared with the direct integral method,the reliability and validity of this method was proved.