Compared to fixed-wing aircraft, telescopic-wing morphing aircraft can improve aerodynamic characteristics and adapt to variable flight environments through the extension and retraction of their wings. However, the control system of a telescopic-wing aircraft is complex and must handle a wide range of operating conditions. Its configuration exhibits typical linear parameter-varying (LPV) characteristics as it changes with the environment and operating conditions, presenting a significant challenge to control algorithms. This paper addresses the model's parameter-varying features and uncertainties during the deformation process of the telescopic wing aircraft, as well as external multi-source disturbances, by designing an Active Disturbance Rejection Control (ADRC) algorithm. Software simulation studies were conducted on the established model and the designed algorithm using the MATLAB/Simulink platform, achieving stable control of the telescopic wing aircraft's deformation flight process and effectively suppressing composite disturbances. Additionally, a sliding mode gain-scheduled control strategy was employed to control the aircraft's deformation flight process, serving as a comparison to the ADRC, thereby verifying the superiority of the ADRC method.