Characterization method of reconstruction resolution of integral imaging technique is significant to the optimization and evaluation of integral imaging system. According to the principle of geometrical optics, considering the pixel discretization effect in the process of digital records, the projection and overlapping of corresponding pixels in image space of three-dimensional reconstruction processing are deeply analyzed, combining the correlations of corresponding pixels in elemental images array. The lateral and depth resolution of integral imaging in image space are defined, and their axial distribution character is studied. The theoretical analysis and experimental results demonstrate that the axial distribution character of lateral and depth resolution of integral imaging is inhomogeneous.