In order to solve the problems of flow out-of-limit and load loss of distribution network caused by planned maintenance， this paper proposed a quantitative analysis method of operation risk classification of intelligent distribution network considering maintenance plan. Firstly， the influence of the maintenance plan on the safe operation of the distribution network was analyzed， and the risk assessment index system of the intelligent distribution network was established from three aspects： operation and maintenance factors， external factors， equipment factors， and so on； secondly， the interval algorithm was introduced， the subjective and objective mixed evaluation method was used to weight the indicators， and the combined weights were obtained by combining the weight factors； thirdly， based on the risk assessment index and its weight， the operation risk level was divided， so as to realize the comprehensive risk quantitative evaluation of the failure probability and impact consequences； finally， combined with the annual operation data of Tianjin power grid， the Ada-DT algorithm was used to predict the risk level， and the operational risk assessment index system and classification method constructed in this paper were effectively verified. The case analysis results showed that the proposed method can effectively classify the operational risk level， identify the weak links of the distribution network and give targeted prevention and control measures， which could provide a reference for the maintenance personnel.