Abstract: The divergence experiment prediction techniques of flat-plate forward-swept wings are presented. The Southwell method, a subcritical divergence experiment technique, was used for prediction of divergence dynamic pressure. By testing, some key techniques in the prediction experiment and critical experiment are introduced.In this experiment, three flat-plate forward-swept wings were tested, of which two are composite flat-plate wings and one is an aluminum flat-plate wing. In order to predict and validate the result of the subcritical experiment, the divergence dynamic pressures were calculated before experiment and the critical divergence wind-tunnel experiments are used. Both the calculating results and testing results indicate that better results can be attained by using the Southwell method. The divergence pressures of these models were calculated by the flexibility method of MSC/NASTRAN and the mode method developed by the authors, while the steady aerodynamics of the subsonic Doublet-Lattice method is used for aerodynamic calculation in both the methods. By making a comparison between the results of calculation, prediction experiment and critical experiment, it can be seen that all the three methods can make better results.