This invention discloses a method for realizing multimodule set up TDM mdoe interconnection and its device, connecting terminals of all interconnected devices by outward circuits, the other terminals of them are linked on a special time slot channel of CT bus, devices being connected are connected to time slot channels of CT bus occupied by related interconnect devices and arranging interfaces for devices being connected. The device includes a CT bus interface unit connecting with the CT bus and interface circuit, a central process unit connecting with CT bus interface and interface circuit and an interface circuit connecting with CT bus interface and the central process unit.