A novel X-ray generator power system in security inspection system is proposed and designed, which has rated voltage of 160 kV and tube current of 0.4 mA-1.2 mA. The technology of high frequency switching power supply is applied to the design, as well as high voltage doubling rectifying and single chip microcomputer control. The application and working principles of X-ray generator are introduced as well as the design methods. Then the functional configuration of the proposed X-ray generator is listed, including the high voltage and filament high frequency inverter, high voltage doubling rectifying circuit and the controlling system. The topological structure, design process and simulating result of the functional component are also discussed. At last, the experiment results and scanned images of the security inspection system are presented, indicating the technical parameters of the proposed X-ray generator fully meet the requirement of the security inspection equipment.