The calculation and analysis of transmission loss is an important part of the analysis of power grid operation.And it is of great significance to make an empirical analysis on transmission loss of Jiangsu power grid during the process of its planning and development.According to the transmission loss calculation methods using DC power flow，this paper uses the power system operation simulation software platform（GOPT），and presents an empirical analysis of the transmission loss of Jiangsu power grid.The years of 2012 and 2015 are taken as level years.Considering different schemes of high voltage transmission planning，this paper carries out the network loss satatistics and empirical analysis based on different regions and different line types of Jiangsu power grid.