With the continuous advancement of line loss lean management, the accuracy of transmission line loss calculations is becoming more and more important. The current line loss calculation method does not consider the load level, clock accuracy, and the influence of the metering device, resulting in a large difference between the actual statistics and the calculated results. It is not conducive to the lean development of line loss management. Based on the existing theoretical line loss calculation method, this paper analyzes the statistical line loss influence amount, and proposes a multiparameter correction algorithm to improve the accuracy of line loss calculation. The effectiveness of the method is proven by taking the ChongqingEnshi 500 kV ultra high voltage transmission line as a numerical example.