Dealing with large-scale projects, traditional database analysis and design methods cannot reflect the actual business requirements to the most extent, which will lead to the difficulty in extending and maintaining the system. Based on domain-driven design, business requirements can be accurately mapped into computer languages, and guide the development of micro services by abstracting complex business into clearly defined domains.Through the demand analysis, business object identification and aggregation division of the power distribution and sale, a business domain with high aggregation and low coupling is formed, which makes the complexity of the subsequent development system modules controllable, reusable and easy to change.