In order to achieve the goal of rapid assembly construction of steel-concrete composite beams and the flexible disassembly of the deteriorated beams，a demountable circular perforated steel tube connector was proposed in this paper. The general finite element software ABAQUS was used to simulate the push-out tests on the proposed shear connectors. The effects of the height，thickness， center angle of perforated holes，the strength of steel and concrete on the shear behavior of proposed connectors were investigated. The results show that the shear capacity of the connectors can be improved by increasing the thickness of tube，the strength of the steel，and reducing the height of the hole. However，the center angle of the hole and the strength of the concrete has little effect on the shear performance. Then，the calculation formula was proposed to predict the yield shear strength of connector based on the plastic beam theory. The result was compared with that of the finite element calculation，verifying the validity of the derived formula.