The experimental platform of bipolar high-voltage pulse power supply with an output voltage amplitude of 0-20 kV and pulse repetition rate of 0.25-20 kHz is constructed. The influence of parasitic parameters of the pulse transformer and load characteristics on the output pulse waveform is studied. By the complex frequency domain analysis method, the effects of parasitic parameters of the transformer on the rising edge, flat top, and falling edge of the output pulse wave are analyzed theoretically, which are further indirectly verified by changing the winding scheme of the transformer. It is found that the larger the distributed capacitance and leakage inductance of the transformer are, the longer the rising time and falling time of the voltage pulse are, and the larger the overshoot voltage is. An optimization winding scheme of the pulse transformer is proposed in that the secondary winding is evenly and densely wound, the primary winding is evenly and loosely wound, and the number of turns is as high as possible. Furthermore, the influence of load characteristics on the output high-voltage pulse waveform is analyzed. (1) When the resistance increases (5-50 kΩ), the overshoot voltage increases, and the rising time and falling time of the voltage pulse decreases. (2) When a resistor is connected in series with small capacitors, the overshoot voltage increases significantly. If the capacitance is higher than a certain value, the output pulse waveform will be the same as that in the case of a pure resistor. (3) When a resistor is connected in series with an inductor, the falling time of the voltage pulse becomes longer.