Abstract: Based on the operating characteristics of the DC blocking devices, this paper analyzes the influence of the DC blocking devices on the DC current near the neutral point of the transformers, and proposes a multi-objective optimization configuration method for capacitor blocking devices based on the field-circuit coupling model and improved differential evolution algorithm. Firstly, a transformer equivalent model and a soil layering model are established respectively. And then, the two models are combined into an equivalent field-circuit coupling model. The finite element method is adopted to solve the DC current at the neutral point of each transformer. Under the condition that the DC current at the neutral point of each transformer is lower than the limit, an optimal configuration model is established with the minimum number of installed devices and the minimum total DC at neutral points of the entire transformers as the objective function. Finally, the effectiveness and superiority of the proposed method is validated through simulation study of a DC transmission project, which shows that the configuration scheme of DC blocking devices obtained with this method can effectively suppress the phenomenon of DC bias and save costs.