Integral imaging is a promising technology for 3D imaging and display. This paper reports the 3D spatial-resolution research based on reconstructed 3D space. Through geometric analysis of the reconstructed optical distribution from all the element images that attend recording, the relationship among microlens parameters, planar-recording resolution, and 3D spatial resolution was obtained. The effect of microlens parameter accuracy on the reconstructed position error also was discussed. The research was carried on the depth priority integral imaging system (DPII). The results can be used in the optimal design of integral imaging.