The wet dual-clutch transmission (DCT) controls clutch engagement via a hydraulic actuator to facilitate smooth starting and gearshifts. The quality of these operations is directly influenced by the hydraulic actuator's precision in pressure control. However, uncertainties, such as variations in the dynamic model parameters of the hydraulic actuator and modeling errors, can impact the effectiveness of pressure control. Furthermore, the intricate nonlinear characteristics of the hydraulic actuator pose significant challenges in designing an appropriate hydraulic controller. In response to these challenges, we propose an adaptive pressure control method for the hydraulic actuator, leveraging a T-S fuzzy model and an extended state observer. Firstly, a dynamic model is established for the clutch hydraulic actuator that comprehensively accounts for its nonlinear attributes. An extended state observer is then designed to estimate variables that are arduous to measure directly, including parameter fluctuations, modeling inaccuracies, and the state variables. Building upon this foundation, the T-S fuzzy modeling technique is employed to approximate the nonlinear components embedded within the dynamic model, and the backstepping method is employed to design an adaptive pressure controller for the hydraulic actuator. Simulation verification results demonstrate the efficacy and robustness of the adaptive pressure control method in addressing parameter fluctuations and other pertinent factors.