This paper presents an estimation method of distribution network reliability planning Investment Based on sequence linearization correlation analysis. Firstly, the planning business index closely related to reliability are selected, and the control objectives of reliability index are decomposed into the promotion objectives of each planning business index through sequence linearization correlation analysis. Then, the typical engineering construction scenarios corresponding to each planning business index are constructed, and the investment required to achieve the corresponding promotion objectives of business index is estimated according to the typical scenarios, Finally, the total investment of reliability planning is obtained. The example shows that the method can be applied to the actual distribution network with complex grid conditions and various planning schemes, and can provide powerful guidance for power supply enterprises to improve the efficiency of capital use