Air springs of traditional air suspension are interlinked, which constructs the structure of Interlinked Air Suspension. Interconnection of air springs changes the stiffness of air suspension and influences its performance, which provides a way for improvement via appropriate control of interlink. The structure and working principle of interconnected air suspension is analyzed, and the prototype vehicle with such suspension and its testing system are established. Experimental results reveal that lateral interlink of air suspension significantly reduces the vertical acceleration of sprung mass, body roll angle and roll acceleration in intermediate frequency(5-9Hz), while makes the dynamic suspension deflection larger. And for small road excitation, interlinked air suspension shows less improvement for vehicle performance compared with large road excitation. Through the analysis of testing results, this paper summarizes the design principles of Interlinked Air Suspension, which can be used as foundation of the design and application of Interlinked Air Suspension.