The most common type of morphing wing in the field of intelligent aircraft design for the future is variable camber, which offers a wealth of opportunities. This paper addresses the design requirements of a multi-state, continuously variable camber wing and proposes a novel design scheme integrating a modular rigid-flexible coupling structure, cross-leaf hinge, and multi-stage shape memory alloy (SMA) actuators. According to the scheme, the equivalent stiffness structural mechanics model of single-stage and multi-stage modular elements is derived by combining the equivalent stiffness calculation method of the cross-leaf hinge, and the comparison and verification are completed by finite element analysis. Furthermore, a quasi-static fluid-structure coupling analysis model was established, verifying the proposed variable camber wing scheme’s multi-state adjustment capability and adaptability under various conditions using SMA’s full phase transition driving, and providing the impact patterns of each deformation state on aerodynamic coefficients. Finally, a conceptual prototype was developed, and a testing platform was constructed. A feedforward open-loop control technique based on multi-state deformation control was successfully implemented, confirming the engineering feasibility of the suggested multi-state variable camber wing design.