Abstract: The overall electricity demand for social production and residents' lives is constantly increasing, and higher requirements are put forward for the operation quality of distribution network transformers. When the distribution transformer experiences heavy overload and low voltage, it can lead to a decrease in power supply quality, which has a negative impact on the normal electricity consumption of surrounding residents. This article is based on the sample data of over 1500 distribution transformers in the distribution network of Mengzi City in the past two years on the electric energy data platform of Yunnan Power Grid Co., Ltd. Firstly, it briefly describes the definition of heavy overload and its different manifestations. At the same time, it visually analyzes the current situation of heavy overload transformers in the distribution network of Mengzi City. Then, it elaborates on the causes of heavy overload in different forms of distribution transformers, analyzes typical governance measures, and provides examples of governance effectiveness.