Abstract: A pulse generator based on pulse forming line and variable impedance transmission line of glycerol medium is studied. The generator is composed of a gas main switch at its rear, a Tesla transformer, a double helix Blumlein line, a variable impedance transmission line and a load. This paper mainly researches the design of insulation and voltage resistance technology of the double helix Blumlein line and the variable impedance transmission line in the common outer cylinder, and the influence of switch position on the output waveform of the generator. Through theoretical analysis, simulation, structural optimization and experimental research, key problems such as structural design, insulation and voltage resistance and load matching are solved. Thus, the compactness and miniaturization of the driving source are improved. The experimental results show that the high power pulse generator can realize quasi-square wave pulse signal with the output peak voltage of 177 kV, the output pulse width of 101.4 ns on the load of 50 Ω.