According to the load characteristics of transmission line, this paper analyzed the current transmission-line codes between domestic and overseas, compared the tension calculation under main working conditions combined with examples. The results indicate that the tension loads derived from GB 50545—2010, which are treated as independent variables in calculation and loads combination, are larger than others derived from the other codes: the earth wire tension increases by 16%~26% and the conductors tension increases by 12%~16%.