Abstract: The transonic aerodynamic nonlinearity induced by shock wave motion and flow separation may significantly change the flutter characteristics of a morphing aircraft during the morphing process. It is a challenge for the lightweight structural design of morphing aircraft. This paper proposes a data-driven transonic aeroelastic modeling method for the wing with morphing flap. The flutter boundary of the morphing wing with discrete change of trailing edge camber can be efficiently and accurately predicted. Firstly, a numerical simulation method based on computational fluid dynamics is developed to simulate the transonic unsteady aerodynamics of the wing with morphing flap. The snapshot data of pressure and aerodynamic response on the wing surface subjected to a given excitation signal is collected. Then, using the obtained training data, a reduced-order state-space model is established based on the combination of proper orthogonal decomposition (POD) and dynamic mode decomposition with control (DMDc). Finally,