The invention discloses a deformable triple-hulled vessel based on an inflatable airbag. The deformable triple-hulled vessel comprises a main vessel body, containing troughs are arranged in the two sides of the main vessel body respectively, a hinge shaft is arranged in each containing trough, a connecting bridge capable of rotating around the axis of the hinge shaft is hinged to each hinge shaft, an airbag sheet body is connected to each connecting bridge, and the airbag sheet bodies can be contracted into the connecting bridges under a compression state and can stretch out of the connecting bridges and extend underwater under an air inflation state. The airbag sheet bodies are connected with air pumps on the main vessel body. Through the structure, a mono-hull vessel is converted into the triple-hulled vessel, the problem that the stability of the common mono-hull vessel is poor in the sailing process is solved, meanwhile, the problems that a dock where an original fixed sheet body triple-hulled vessel berths is not changed and the manufacturing process of a sheet body structure is large in difficulty are avoided, and the deformable triple-hulled vessel is reasonable in structure, easy to manufacture, convenient to use, especially suitable for high-speed vessels of small and medium sizes and high in promotional value.