The single-phase load and the three-phase load in the low-voltage station area are mixed and the wiring system is special. The three-phase unbalance is common and serious, causing more serious unbalanced additional line loss. The difference in the load size and spatial distribution of each phase causes the imbalance in the low-voltage station area to be great different, and the impact on the unbalanced line loss cannot be ignored. In order to improve the accuracy of the line loss calculation in the low-voltage station area, a three-phase unbalanced line loss calculation model that considers the load distribution based on the forward method is constructed, and an unbalanced correction coefficient considering the load distribution to characterize the effect of the three-phase distribution on the line loss is proposed. In order to facilitate the application, based on the four typical load distributions, the model is equivalently simplified, and a three-phase unbalanced line loss calculation method that is suitable for two types of typical load distribution scenarios and considering the load distribution is proposed. The calculation example verifies the accuracy and feasibility of the method, and can provide a reference for improving the accuracy of line loss calculation in the low-voltage station area.