Proposed in this paper is an optimization-based method to solve the initial equilibrium problem of the cable-net surface tensioned with adjustable cables,with the effect of cable self weight being considered and with the active cable-net reflector structure being employed. In this method,the cable length is considered as the design variable,the minimum unbalanced force of cable-net nodes is taken as the optimization objective,and the corresponding constraints on the tensions of adjustable cables and cable-net surface are introduced. Thus,it can easily determine the initial cable length when the structural geometry and the boundary conditions are known. Moreover,the mechanical characteristics of cables considering their self weight are analyzed according to the analytical expression of elastic catenary,based on which the sensitivity of the optimization model is obtained. Finally,a detailed analysis procedure is presented with the numerical example of the active cable-net reflector,and the initial cable length and the tension distribution of the structure are obtained. The results demonstrate that the proposed method is effective.