Interconnected air suspension system can change a vehicle’s operation characteristics by exchanging gas between air springs. In this paper, we analyze the structure and working principle of interconnected air suspension based on thermodynamics and vehicle dynamics. Then air suspension’s mathematical model including interconnected characteristics is established to study gas exchange principle of air suspension system. Interconnected pipeline parameters and excitation phase differences’ influence on characteristics of air suspension system in whole vehicle are calculated and analyzed. Simulation results show that the stiffness of air suspension is reduced when air springs of the suspension system are interconnected, as well as it decreases gradually with the increase of interconnected pipeline diameter; the stiffness of air springs is minimum if the excitation phase difference between both sides of air springs is 180 degrees. In the condition of twist pavement (tires at diagonal positions are excited simultaneously), the interconnected air suspension can reduce dynamic load difference between left tire and right tire markedly, which can increase adhesive force between tire and road effectively. On the other hand, with the condition of double lane-change testing, the bigger the interconnected pipeline diameter is, the larger the roll angle of car body is. Meanwhile, the increasing pipeline diameter has no obvious influence on roll angle when it is over 10 mm.