Abstract: Distribution network dispatch is a coordination organization in the distribution network. During operation, it is usually commanded and controlled based on past experience. It is difficult to accurately measure the degree of loss, resulting in a low reliability rate of power supply in the distribution network. Therefore, the application of reliability assessment in the dispatching operation of distribution network is studied. According to the line loss status of the distribution network, the line loss index of the distribution network is obtained, and the reliability index of the line power supply is used as an evaluation index to formulate the operation mode. Apply the expression of probability distribution function to quantify the reliability index of line power supply. The concept of state space method is introduced, and the line factor model is constructed based on reliability assessment, and the design of the dispatching operation method of the distribution network is completed. The experimental results show that the average power supply reliability rate of the proposed method is high, which proves that the proposed method has better effect in the dispatching operation of the distribution network.