The series formula and its corresponding differential equation of fish-eye lens′ stop spherical aberration have been brought forward. Calculating the approximation of the stop spherical aberration according to these formulas,and then adopting iteration, we can confirm the entrance pupil′s position and primary ray accurately. Furthermore,it analyzes the stop′s coma,discusses the special “conjugate” relation between aperture stop and entrance pupil, and how to improve the uniformity of image plane illuminance by using aberration vignetting.Ray′s total reflection or no-intersection at refracting surface is called “ray overflow”.Frequent ray overflows in the optical automatic design of fish-eye lens makes its CAD very hard.Using Aitkin Interpolation to fill up the intersection points of overflow-rays at image plane can ensure the optimization process persistently to go along,and then clearing up the overflow gradually.In the end,it expounds the successive approach method to confirm the boundary of abaxial beams,a