Abstract: A 150 kV/30 kW high voltage pulse electron beam welding power source was developed. The bias pulse power source topology and control technique about base beam current, peak beam current, pulse beam duty, pulse beam frequency were introduced. Not only the biggest peak beam current up to 200 mA has been exported by this power source at 0-1 kHz, but also weld technology parameters are expediently adjusted. The 1Cr18Ni9Ti stainless steel work pieces had been welded by electron beam welding and pulse electron beam welding. These weld bead shapes had been studied and analyzed. In contrast with electron beam welding, weld penetration will be increased by pulse electron beam welding introduced. At the immovable pulse beam duty, the weld faults will be reduced with the pulse beam frequency being increased. Through these weld tests, besides beam frequency and duty are substantiated key technique parameters for weld shapes, it also shows that pulse modulated bias power source technique is an applicable technology to achieve high voltage pulse electron beam.