A novel indoor mobile 7200kV impulse voltage generator comprises main capacitors. Insulated pillars are arranged beside the main capacitors. The main capacitors are externally hung on the insulated pillars, and are distributed in a V shape beside the insulated pillars. Wave modulating elements arranged beside the insulated pillars. Insulated ladders are arranged between the insulated pillars and the wave modulating elements. The wave modulating elements are connected in series with each other. A multiple-electrode ignition device is arranged beside the wave modulating elements. The structure is compact, and the inductance is small. The two wave modulating elements are of a serial connection structure, so that the wave modulation range of the wave modulating elements is wide. By adoption of a tower-shaped building block structure, installation is convenient. The insulated ladders and insulated platforms are arranged to bring convenience to the debugging personnel in climbing for maintenance. The bottom of the impulse voltage generator is provided with air cushions which enable the impulse voltage generator to move back and forth. The multiple-electrode ignition device makes the ignition effect good and adjustment convenient.