The spiral transformer is a type of vector inversion generator composed of a double-layer metal strip winding. By closing a switch, the energy stored in the strip is released, generating a high-voltage pulse. Compared with other generators, the spiral transformer has a simple structure and can generate voltage pulses with amplitudes ranging from tens to hundreds of kilovolts. This paper presents the development of a spiral transformer used to generate nanosecond pulse high voltage. Through theoretical analysis and modeling, the working principle and circuit structure of the spiral transformer are thoroughly examined. Based on this, a compact air-insulated spiral transformer pulse source with tens of kilovolts was designed and experimentally studied. The results show that a spiral transformer with an axial length of 80 mm and a maximum outer diameter of 74 mm achieves a voltage multiplication ratio of approximately 15 under air insulation conditions, realizing a nanosecond pulse high-voltage output of tens of kilovolts. This demonstrates significant potential for practical applications. Moreover, this paper systematically investigates the boosting efficiency of spiral transformers with typical parameters under different charging voltages and their output characteristics under varying loads.