Abstract: In order to improve the performance of the X-ray source pinhole imaging system, the study on the optimization design of the pinhole imaging system for X-ray source in 10-100 keV was carried out with both theoretical analysis and Monte Carlo simulation. The wavelength and penetration effect of X-ray and angle response of collimator have different influences on the results of the pinhole imaging system. Based on those results, a bottom-shell-like collimator was designed to control the variation of imaging resolution and area. Then the pinhole imaging system with the collimator was verified with Monte Carlo simulation. The results show that the collimator can get the stable imaging resolution and spot brightness, and the relatively accurate orientation and quantitative information of X-ray source below 100 keV can be obtained.