Abstract: The large-scale access to distributed photovoltaics has gradually transformed the traditional distribution network from a single power supply structure to a multi-power supply structure, and the power flow distribution of the distribution network has also changed accordingly. This results in the traditional statistical method of line losses being unable to accurately calculate the line losses rate of distribution network lines containing distributed photovoltaics. Therefore, existing line losses statistical methods need to be improved accordingly. First, several situations of power flow distribution in the distribution network after distributed photovoltaics are analyzed, and then an improved statistical method of line losses is proposed. Finally, the correctness and accuracy of the improved statistical method of line losses statistical method are verified based on actual cases.