<p>This paper addresses the control problem of flight control surface servo systems for near-space vehicles. Such systems are exposed to extreme thermo-mechanical loads caused by long-endurance flight, high-Mach cruising, severe aerodynamic heating and other harsh operating conditions. To tackle this challenge, an adaptive global sliding mode control (AGSMC) strategy with a novel anti-deviation parameter is proposed. Firstly, a continuously differentiable dynamic model is established, which incorporates temperature-dependent characteristic parameters and inherent nonlinearities of the servo system, including backlash and friction. The main advantage of the proposed AGSMC lies in its ability to generate real-time sliding mode trajectories according to time-varying system states. Furthermore, the hyperbolic function-based switching law guarantees rapid error convergence and suppresses deviation from the sliding surface, thereby eliminating chattering in the small-error region. Step response and frequency sweep simulations under multiple temperature conditions validate that the proposed method can effectively suppress chattering, and exhibits superior stability and dynamic performance compared with conventional control algorithms.</p>