Abstract: The present invention provides a cooling structure for high voltage electrical parts of an HEV, in which a plurality of high voltage electrical parts including a DC-DC converter, an inverter, and an air conditioner inverter are arranged on a cross section of a cooling air passage in a direction horizontal to the flow of cooling air, a cooling blower for cooling the high voltage electrical parts is mounted on one side of an electrical part package in the opposite direction, and; and a duct is integrally formed on an upper portion of the blower so that the cooling air passing through the electrical part package is discharged therethrough, thereby being able to supply the cooling air at the same temperature to the plurality of high voltage electrical parts and mount the electrical part package in a relatively small space.