Abstract: Aiming at the problem of large loss of traditional transformer, a single-phase three winding autotransformer is designed. The design optimization of transformer is proposed from many aspects,such as " H-H" epoxy adhesive process,new full inclined seam process,pet tape thermal friction melting binding process,magnetic shunt technology,shielding continuous structure,paper wrapped self-adhesive transposition conductor,epoxy resin pouring processand so on. The performance test shows that compared with the conventional transformer,the no-load loss and on load loss of the single-phase three winding autotransformer are reduced by 40% and 19%respectively,indicating the effectiveness of the structural design and the application of new technology and new materials,which can effectively improve the comprehensive performance of the transformer.