In this paper, the calculation of the suspended-modular-tram car with 5 module and low floor passing through curves was designed to study important parameters such as the rotation angle of the articulated equipment and the rotation angle of the coupler and so on. According to the structure characteristics of the tram car and the basic theory of analytic geometry, the calculation method of the rotation angle of the articulated equipment and couplers when the tram car passing through the plane curve and the vertical curve was deduced. At the same times, the dynamic software was used to simulate the tram car passing through curves. The results were basically consistent with the calculated results. The calculation method proposed in this paper could provide the basis for the selection of articulated equipment, gangway bellows and couplers.