The utility model discloses an oil-gas separation device for an engine and belongs to a part in the technical field of engines. The oil-gas separation device mainly comprises an oil-gas separation chamber. An air inlet pipe and an air outlet pipe are arranged above the oil-gas separation chamber. An oil returning pipe is arranged on the bottom of the oil-gas separation chamber. The oil inlet pipe penetrates through the top of the oil-gas separation chamber and extends to the inner bottom of the oil-gas separation chamber. An oil-gas separator is arranged at an outlet of the air inlet pipe in the oil-gas separation chamber. One side of the oil-gas separation chamber can be provided with a fixing device. The oil-gas separation device is simple in structure, low in cost and convenient to use, the oil-gas separation chamber is arranged outside the engine, the oil-gas separation device in the engine is simplified, and on the basis that the original lubricating effect of the engine cannot be affected, the problem that engine oil is exposed out of the engine is effectively avoided. The oil-gas separation device is mainly used for the engine.