Abstract: In this paper, a topology of non-balanced reactor 24-pluse auto-transformer rectifier was proposed based on the composition of voltage vector. Each phase of the auto-transformer was arranged with five windings, conducting two diodes of four rectifier bridges at synchronization according to the voltage vector superposition of different windings and outputting the line voltage with the maximum vector difference. Conducting the main rectifier bridge and the auxiliary bridge successively according to the time zone of the main and auxiliary vector composition, the rectifier bridges could parallelly output the 24-pluse DC voltage due to the composition form of the asymmetric output voltage. The turn ratio of the auto-transformer, the expression of input current and output voltage were derived, and the system performance was analyzed by calculating the input current harmonic content and the equivalent capacity of transformer. Finally, the rationality of the design was verified by simulation and experiment.