Abstract: The pinhole collimator of gamma camera dedicated to high-energy gamma photon imaging needs special design when placed in high radiation environments for ray source distribution imaging. To simplify the design procedure of pinhole collimator, we introduced some new analytic formulas to describe the relation between parameters and properties. First, the formulas of effective aperture, angle resolution and relative geometric efficiency were deduced by analytical method, and then compared with Monte-Carlo method. The results show that the value provided by analytical method is reliable. Therefore, the analytical design method we introduced for pinhole collimator is simple and useful.