Abstract: A 200-kV flash X-ray radiographic test system based on the principle of Marx generator is introduced. The system has a delay function that it can produce X rays at predetermined time in accordance with the experimental requirement. A 10-stage 200-kV Marx generator has been designed in coaxial structure, and low-jitter field-distortion switches, low-inductance solid-state resistors and ceramic capacitors are used in the pulse generator to shorten the risetime and pulse width of output pulses. The generator was demonstrated to deliver pulses of more than 200 kV onto a 75- load with 100-ns pulse width. Being connected with an X-ray tube through a high-voltage cable, the pulse generator drove the X-ray tube to produce flash X-rays with a pulse width of 70 ns and a dose of 910-6 C/kg at the distance of 0.25 m from the laser source.