Abstract: With the large-scale integration of diversified resources such as distributed generation, electric vehicles (EV), and distributed energy storage, as well as the application of flexible DC technology enabling interconnection between multiple distribution networks, the complexity of line loss calculation has significantly increased. Currently, there is no standardized method for calculating line losses in distribution area with diversified resource integration. This paper establishes a line loss calculation model for diversified distribution networks and refines the model under different scenarios, including those with standard EV chargers, Vehicle-to-Grid (V2G) chargers, and combined V2G chargers with photovoltaic systems. The model accurately outputs line loss rates for AC networks with flexible interconnection and DC microgrids, offering a more precise reflection of line loss under various conditions. Additionally, the paper analyzes the key influencing factors of line losses due to diversified resource integration and proposes strategies to enhance line loss management.