<p>Quick-change devices in modern multifunctional engineering equipment continue to face considerable challenges regarding structural reliability and control responsiveness, which complicates the balance between operational safety and flexibility under high-frequency working conditions. To address these challenges, this study proposes an integrated electro-hydraulic quick-change device capable of rapid attachment replacement and free posture adjustment, aiming to enhance operational efficiency and system integration in complex environments. A three-dimensional model of the device was first established, followed by static and modal simulations to identify stress concentration regions and extract dynamic response characteristics of critical components. Considering structural degradation under multi-source loading, a time-dependent reliability analysis model was developed by integrating P-box modeling concepts with the PHI2 method. This model facilitates interval predictions of component failure probability over its lifecycle under epistemic uncertainty, and its robustness was verified through a numerical case study. Based on this framework, the failure evolution of the swing cylinder and worm-gear mechanism was investigated using the response surface method and Hertz contact theory, revealing the risk-dominant characteristics of the transmission system during its late service stage. Furthermore, a hydraulic–electrical integrated control system was designed, and a co-simulation model combining Simulink and AMESim was implemented to compare the control performance of fuzzy proportional-integral-derivative (PID) and conventional PID strategies in attachment switching operations. Simulation results demonstrate that the proposed control system offers superior response speed, steady-state accuracy, and disturbance rejection capability, effectively supporting stable and efficient operation of the quick-change device under various working conditions.</p>