A novel construction method without scaffold work called as assembly-prestressing form finding loop by loop is presented.Based on the theory of finite displacement,the cycle-forward analysis method is presented for its construction calculation,which adopts the finite element method of generalized geometric nonlinearity combined with the application in the real construction process.By means of the combination of the forward analysis according to real construction sequence and the cycle iteration according to the initial strain increment method of cable force adjustment,the influence of the structural geometric nonlinearity and the loss of prestress are taken into account due to prestressing of tendons in turn and so on.If the initial cable forces derived from the method were used for construction,expected cable forces and shape could be assured easily.Simulation analysis achieved real-time tracking and controlling of the construction status.Finally,according to the procedure and parameters in simulating,a model experimental research on the stage of form finding(namely prestressing)was carried out for suspen-dome structure.The feasibility on the assembly-prestressing form finding method loop by loop was testified.The cycle-forward analysis method was established and numerical simulation was performed,and the results show that it was useful for the design and the construction of similar suspendome structure.