Abstract: Developing a compact flash X-ray tube with high operating voltage is necessary to high energy pulsed X-radiography. The operating principle of the field-emission cold-cathode X-ray tube is described in this paper. A novel compact flash X-ray tube with vacuum insulator stack, the voltage of the tube of 1 MV and exposure of 4.128×10-4 C/kg per pulse, is designed. The stack is composed of ten insulators and nine grading rings in alternating sequence. The length of the stack is 260 mm. Static simulation results show that the highest operating field strength of the tube is 94.8 kV/cm, which is lower than the empirical 120 kV/cm; the highest operating field strength of all the triple piont is 26 kV/cm, also lower than the empirical 30 kV/cm. The cubage of the tube is small and high vacuum will