The development of automotive suspension systems greatly brings along the improvement of vehicle performance. Due to the effectiveness of vehicle performance improvement and easy-of-ride height control with air suspensions, an ride height control (RHC) system and an adjustable damping force control (ADFC) system are integrated together to develop a new suspension system, namely hybrid active air suspension (HAAS) system, by which the ride height tuning and adjustable damping force control can be separately or simultaneously realized. First of all, the numerical models for the RHC system and ADFC system are constructed, followed with the development of control algorithms and tests of the RHC system and ADFC system, respectively. Then, the proposed HAAS system is constructed by integrating the RHC system and ADFC system, and a dynamic quarter car model is constructed for studying the applications and testing of the HAAS system. To practically verify the proposed control methods without too much resource and lab space, a novel quarter car test rig (QCTR) is developed for the HAAS system, so that an online hardware-in-the-loop (HIL) test and measurement can be carried out under real working conditions. In this research, numerical simulations are conducted to determine the suitable control methods for the RHC system and ADFC system, respectively. With the selected control methods, the online HIL tests are implemented for the RHC system and ADFC system. Subsequently, a new coupling control method is proposed and evaluated for the HAAS system in order to solve the interaction between the RHC system and ADFC system. Both the simulations and the experimental tests show that the proposed HAAS is acceptable in ride height and damping force control for the vehicle. Also, the ride iii comfort, road holding capability and handling stability of the vehicle can be effectively improved. In addition, with the proposed coupling control method, the conflict between the RHC system and ADFC system can be effectively solved, and the performance of the HAAS can be further improved as well. Overall speaking, the proposed HAAS system is a promising suspension system with ease-of-ride height adjustment and superior dynamic performance for vehicles.