To enhance the deformable flexibility and stiffness of an aircraft wing and make it more versatile for multiple tasks, a modular large-scale deformable wing mechanism based on a parallelogram mechanism is proposed. The mechanism composition, degrees of freedom, and kinematic characteristics are analyzed. First, a new modular deformable wing mechanism is designed using the parallelogram mechanism. The structure is briefly outlined, the mechanism’s degree of freedom is calculated, and its deformation process is analyzed. Next, a kinematic model is established using the closed-loop vector method, and the kinematic characteristics of components, such as angle, angular velocity, and angular acceleration, are studied. Finally, the numerical results of the kinematic model are compared with the simulation data. The comparison shows a strong agreement between the two, confirming the accuracy of the kinematic model. The proposed deformable wing mechanism demonstrates stable and smooth motion, with continuous large-scale deformation that offers higher flexibility and reliability.