The invention discloses a mixed combustion type engine, which is a novel energy-saving and emission-reducing engine. The mixed combustion type engine consists of an oil-gas input device, a one-way valve, an ignition device, a combustion chamber, a heat insulation layer, a pressure sensor, a safety valve, a flow adjusting device, an engine and an angle sensor. The combustion chamber and the engine are separately designed in the mixed combustion type engine, fuel and air are adjusted by the oil-gas input device and then sprayed to the combustion chamber in a multi-point mode, the ignition device carries out ignition, the fuel is continuously combusted and gasified in the combustion chamber, the temperature is raised, the air is expanded with heat, the fuel and the air generate high pressure in the combustion chamber together, and the high pressure is controlled by the flow adjusting device and propels the engine to rotate. The mixed combustion type engine has the advantages of an internal-combustion engine and an external-combustion engine, the fuel is continuously and stably combusted, the heat is fully utilized, the utilization efficiency of the fuel is high, little exhaust is discharged, the engine only has working and exhaust strokes, the working efficiency is high, the idle working condition is good, the working temperature is low, the cooling requirement is low, the process requirements of the combustion chamber and the engine are low, and an efficient device can be conveniently designed and manufactured.