The combined-cycle engine powered aircraft demonstrates horizontal takeoff capability from conventional civil airfields, exhibiting adaptability to diverse operational scenarios and work at speeds in excess of Ma=5. The integration of morphing aerodynamic configurations into this aircraft architecture significantly enhances its operational speed range and spatial coverage, thereby optimizing flight performance across extended speed regimes and expansive flight envelopes. An aircraft model with variable-sweep wing configuration was established including the shape structure, aerodynamic model and power model, and the coupling characteristics in the model were analysed. The trajectory in the take-off and climbing phase were segmentally optimised based on the Gaussian pseudo-spectral method. Comparative analysis between morphing-wing configurations and fixed-geometry counterparts revealed critical performance advantages. Simulation results demonstrate that the proposed wide-speed-range morphing aircraft model exhibits dual-coupling characteristics involving propulsion-flight interaction and morphodynamic coupling. It also proves that the sweep angle changing can effectively improve the climbing efficiency and fuel saving performance in the take-off and climbing phase.