Abstract: Multi-habitat is one of the tendencies for the future development of unmanned vehicles. This paper presents a novel concept of amphibious unmanned vehicles， whose air propeller arrangement corresponds to the arrangement of four-rotor aircrafts， and the above-water design is in the form similar to that of pentamarans. Then， a series of rolling tests are performed for the model， and the study of its rolling characteristic under different side hull positions is conducted based on the system identification method. The results successfully verify the reliability of the identification method as well as the correctness of the mathematical model.