The invention relates to a dynamic engine and aims at providing a pneumatic internal combustion hybrid engine. The engine comprises at least one pneumatic motor, at least one internal combustion engine and a high-pressure air tank, wherein the outlet pipeline of the high-pressure air tank is connected to the air inlet pipe of the pneumatic motor through a check valve and a pressure regulating mechanism; the air inlet pipe of the internal combustion engine is respectively connected with the exhaust pipe of the pneumatic motor and an air inlet; and a pneumatic motor crankshaft and an internal combustion engine crankshaft are connected in a sub-crankshaft mode through a crankshaft coupling mechanism. The hybrid engine provided by the invention has the advantages that air can be exhausted by fully utilizing the high pressure and lower temperature of the pneumatic motor, a supercharging effect can be formed for the internal combustion engine, and the size of the intercooler of the air intake system of the internal combustion engine can be reduced appropriately; and the pneumatic motor and the internal combustion engine are connected in a sub-crankshaft coupling mode so as to output motive power externally, thus the pneumatic motor and the internal combustion engine can operate on the respective optimal regions.