This paper addresses the deployment dynamic analysis of antennas mainly composing of deployable truss and cable net. The antennas are deployed by retracting driving cables, which pass through pulleys fixed on the deployable truss successively. An analytical model is first proposed for the driving cable system where the nodal position and the transmission lengths of the cable segment between two adjacent pulleys are selected as the generalized coordinates. This model could simulate the dynamics of the driving cables with time-varying length. Then, the flexible multibody dynamic model of the deployable antenna including the flexible deployable truss and cable net is established. The absolute nodal coordinate formulation is employed to model the flexible deformation of the truss and the tension of the cable net. The method is demonstrated by analyzing the deployment of a cylindrical mesh antenna. The deployment experiment of the antenna shows that the proposed method can correctly predict the driving force and length variation of the driving cables, the bending deformation of the flexible truss, and the deployment process.