In recent years, due to the rapid development of the national economy, the country has invested heavily in the distribution network, resulting in many new problems in the planning of urban distribution networks. The distribution network auxiliary decision-making system was adopted to improve and expand the existing public information mode, enabling various systems in the distribution network to effectively transmit information, thereby better achieving information fusion of various systems in the distribution network. In the auxiliary decision-making system, intelligent perception and big data technology were integrated to proactively discover and solve problems. In the 10 node tests selected in this article, the power supply safety score was 8.9 and the system reliability score was 8.1. The distribution network fault diagnosis and auxiliary decision-making plan provided in this article is for the power company to develop maintenance plans and improve the reliability and stability of power supply.