The invention belongs to the technical field of energy saving of an electric power system, and particularly relates to a line optimum transmission power calculation method considering parallel connection reactor and corona loss. By aiming at the characteristic of low loss of a 750 kV line, a 750kV line integral consumption model is built, various kinds of loss (which is mainly the high-voltage reactor loss, the circuit corona loss and the like) generally ignored at the lower voltage stage are integrally considered. The 750kV line optimum transmission power calculation method provided by the invention has the advantages that the 750kV line loss can be effectively combined for forming features, so that the concept and the method for measuring the most economical 750kV line operation measure using the transmission power as the natural power are improved and completed, and the more reasonable basis is provided for the economic operation of the 750kV line.