Abstract: The paper presents a design of high voltage pulse generator based on high voltage switch formed by a stack of metal oxide semiconductor field-effect transistor (MOSFET). Two pulses at both ends of out metal layer in transmission line are generated by the self-matched transmission line circuit using high voltage switch made by many opto-isolator triggering MOSFETs in series. Then, a higher power pulse with amplitude of 20 kV on 200 Ω load, duration of about 40 ns and repetition frequency of 20 kHz is generated by the technique that transmission line transformers (TLTs) synthesize two pulses. An emulational circuit model is designed after the structure of pulse generation device is analyzed. The distortion of output pulse is analyzed by the model. Factors influencing the output pulse waveform are discussed. A reference for optimizing output pulse is put forward.