Abstract: This article proposes a finite-time adaptive fuzzy control method based on state observers for the dual-rod cylinder in the aerospace propulsion servo system. Despite considerable research on the theory of adaptive fuzzy control, both voltage saturation and output constraint have not yet been considered simultaneously in pneumatic cylinder control. According to fuzzy logic system, a state observer is designed to estimate the unmeasurable states in the pneumatic dual-rod cylinder. An output feedback controller is developed based on backstepping scheme and the output constraint is handled via the barrier Lyapunov functions. The paper sets up an experimental platform based on a dual-rod cylinder and demonstrates that all closed-loop signals are bounded, and the output remains within the constrained set. Experiment results which achieve an accuracy of 0.1mm for sinusoidal tracking verify the effectiveness of the proposed method.