Abstract: The mechanical behavior and horizontal bearing capacity of the connection joint between steel roof and reinforced concrete structure under earthquake were investigated.According to the experimental studies on three 1/2 scaled models of the real connection joint between the steel roof and the concrete structure under low cyclic reversed loading,the failure process and patterns were obtained and load-carrying capacity,ductility and energy dissipation were analyzed.Results show that the bearing capacity of the connection joint is less than the yielding capacity of the connecting bolts alone.The final damage reason of the connection joint is the crack of the concrete structure around the anchor bolts.The hysteresis curve of the connection joint with strong capability of energy was full.According to the comparative analysis of test results and theoretical calculations,the formulas of the bearing capacity of the connection joint between steel roof and reinforced concrete structure were presented,the calculated results agree well with those of the test.