The invention relates to a novel polarity-change charging transformer for an impulse voltage generator. The novel polarity-change charging transformer is characterized by comprising an outer shell (1), wherein a high-voltage silicon stack (2) is arranged in the outer shell (1); a drive device (3) is arranged on the outer shell (1) and drives the high-voltage silicon stack (2) to rotate; a high-voltage cable (4) which extends to the inside of the outer shell (1) is arranged on the outer shell (1); the high-voltage cable (4) is in contact with the high-voltage silicon stack (2); and an insulating cylinder (5) is arranged outside the high-voltage cable (4) for guiding. The high-voltage cable is adopted for leading; and reliable contact of a pressure spring and the high-voltage silicon stack is ensured by the pressure spring. Due to the flexible characteristic of the cable, the novel polarity-change charging transformer has the advantages of being convenient to connect, not easy to damage and easy to repair.