Abstract: In order to realize the fast and accurate identification of distribution transformer winding materials, we proposed a nondestructive identification method of transformer winding materials based on harmonic effect and experimentally verified it based on the existing research. Firstly, we studied the theoretical mechanism under harmonic effect, and analyzed the feasibility of material identification of transformer winding based on harmonic effect method according to the calculation formula of harmonic resistance of transformer winding. Then, the corresponding test model and equivalent circuit were given according to the characteristics of common connection groups of distribution transformers and the error effect of the experimental equipment was analyzed. Finally, we used the distribution transformers with different winding materials for experimental verification and explained the engineering practicability of this method. The experimental results show that the method described in the article is fast and accurate, and can quickly and effectively identify the winding material of distribution transformers, which has a broad engineering application prospect.