Abstract: The conceptional design of a 20 MA/300 ns direct-driven Z-pinch pulsed power driver based on Marx generators is presented, whose Marx generators are composed of 18 series stages with 1.0 F/40 nH/100 kV metal shell capacitors and 100 kV/200 kA gas switches. It has 40 modules in parallel, each consisting of six Marx generators driving the water transmission line. The circuit scheme of the pulsed power driver is set up through PSpice, and the influences of Marx erection jitter on load current are simulated. The results show that when the Marx erection jitter increases from 10 to 60 ns, the peak current varies from 21.0 to 19.8 MA, the rise time of load current is from 282 to 289 ns, while the full width at half magnitude of load current is constant. The effects of the Marx erection jitter on load current declines with the number of Marx generators in parallel increasing. The load current is of maximum when the water line impedance is 4.2 .