We propose a fundus imaging system based on the tomographic adaptive optics instead of conventional adaptive optics to increase the limited field of view. The performance of the proposed system is studied with Zemax and the simulation object, Liou-Brennan (LB) eye model. The human eye aberrations are described by Zernike fringe polynomials within 20° field of view to obtain the type and value of fundus aberrations. The results indicate that the proposed system extends the field of view from 1.2° to 3° compared with the conventional adaptive optics system. How to select the conjugated position of the deformable mirror for adaptive optics based fundus imaging systems is investigated. It figures that the deformable mirror can be optically conjugated at 3 mm before the exit pupil of eye for both the conventional adaptive optics system and the proposed system, and the position is also conjugated with cornea.