The utility model discloses a baffle for oil -gas separation, including being used for installing the baffle body in the cylinder end lid, be equipped with on the baffle body and be used for communicateing the baffle body oil gallery in space from top to bottom. The utility model discloses can be when realizing oil -gas separation, the flow area of the machine oil that reduces to flow back, it is internal to make machine oil flow back to the crankcase fast, avoids machine oil to reform the oil vapour at the backward flow in -process.