Abstract: FRP composite material has good insulation and stain resistance，which can greatly improve the safety level of transmission line and reduce maintenance cost． Based on the background of 380 kV transmission line reconstruction，in the project，two kinds of specifications of FRP composite steel casing 200 10 and 272 12 were used，and their tensile properties were studied，the test was divided into the design load test ( engineering application) and ultimate bearing capacity test ( failure mode) ; the load-displacement curves，strain disciplinarian law and failure mode etc were got． It was found that the bearing capacity of steel casing of bonded joints was mainly decided by the adhesive strength，the failure mode is brittleness form． Finally，in view of the tensile design of the FRP composite bushing，some design suggestions were proposed．