The invention discloses a rolling mould for manufacturing a variable section heating body of a 24-KW voltage stabilizer in a nuclear power plant, which comprises components such as roller moulds A (1), roller moulds B (2), a cover plate (3), a pressing plate (4), a pressing-down hand wheel (5), a supporting plate (6), a bearing sleeve (8) and a frame (10), wherein a circle of grooves, of which the section is semi-circular or semi-elliptic, is formed in the middles of cylinders on a plurality of sets of roller moulds A and roller moulds B; and the plurality of sets of roller moulds A and roller moulds B, of which semi-circular diameter or the length of a semi-elliptic short shaft is reduced gradually, are used sequentially for rolling according to the size requirement of a processing object. By the rolling mould, the variable section heating body which is subjected to checking of surface quality, shape size, elongation rate and the fit of transition sections and meets a use requirement of the 24-KW voltage stabilizer in the nuclear power plant can be manufactured, so that correlation technical requirements of foreign like products are met totally.