Abstract: Aiming at the online trajectory planning problem of hypersonic morphing vehicles with waypoint constraints, a multi-stage continuous solution-based variable time-domain receding planning sequential convex optimization technique was proposed by combining the sequential convex optimization method with the receding planning method. Firstly, the impact of morphing on the aerodynamic characteristics of the vehicle was analyzed, and a hypersonic morphing vehicle aerodynamic model and a dynamic model were constructed; for the trajectory planning problem of the vehicle with variable spreading length, convexization and discretization were carried out to obtain the convex problem of trajectory planning; the relaxation solution technique was adopted, and a method of reliance-domain relaxation and terminal constraint relaxation was proposed, which improved the convergence of the algorithm, and a control volume change rate constraint was used to avoid control volume jitter. Hereby, a multi-stage continuous solution-based receding planning sequential convex optimization technique was proposed. On this basis, in order to improve the anti-disturbance ability of the hypersonic morphing vehicle in complex environments, atmospheric deviation and other interference conditions, the receding time-domain idea was introduced into the sequential convex optimization framework, which improved the real-time performance and robustness of the algorithm. Finally, the validity of the proposed method and the superiority of the variable-spread-length vehicle in the trajectory planning problem were verified by the trajectory planning simulation results.