Abstract: A pulsed power generator (PPG-Ⅰ) with a voltage of 500 kV in amplitude, a current of 400 kA in amplitude and 100 ns in pulse width was constructed. The development of X-pinches and the early stages of wire-array Z-pinches were investigated by X-ray backlighting using the X-pinch driven by PPG-Ⅰ as X-ray source. The plasma explosion and implosion near the cross point of the X-shaped wires can be clearly seen from a series of backlighting images taken at different time during X-pinch discharge. To study the early behavior of the plasma in wire-array Z-pinches, an X-pinch installed in the place of a current-return rod was used as the X-ray source to backlight a wire-array Z-pinch installed in the center between the anode and the cathode. The plasma formation, the inter-wire plasma merging,