The utility model discloses an engine piston, the piston includes: the oil feed way of cooling machine oil, oil feed say that vertical setting is in the piston, internal cooling oil duct, internal cooling oil duct level set up in the piston, and the internal cooling oil duct forms the oil inlet with the interface that the oil feed was said, oil return way, oil return say that vertical setting in the piston, just communicates with the internal cooling oil duct, water conservancy diversion spare, the oil inlet department of cooling oil duct including water conservancy diversion spare is fixed, and the water conservancy diversion facial features of water conservancy diversion spare is said to the oil feed and the slope of internal cooling oil duct. This engine piston is provided with the guide plate in oil inlet department, and the flow direction of control machine oil makes most machine oil spout inside cooling oil duct, reduces the proportion of backflowing of machine oil, and the machine oil that gets into the internal cooling oil duct increases, makes the cooling efficiency improvement of piston to improve the reliability of piston, under the condition that target temperature is the same of piston, this piston can reduce the injection quantity of cooling jet, has reduced the oil consumption of machine oil.