Vacuum oil purifier is designed according to the different boiling point of water and oil. It consists of vacuum heating tank, fine filter, condenser, prefilter, water tank, vacuum pump, oil drain pump and electrical cabinet. The vacuum pump draws out the air in the vacuum tank to form a vacuum. Under the action of atmospheric pressure, the external oil enters the primary filter through the inlet pipe, removes the larger particles, and then enters the heating tank, and the oil is heated to 40~75 °C. Automatic oil bleed valve, which automatically controls the amount of oil entering and leaving the vacuum tank. The heated oil is rapidly swirled by the spray wings to separate the oil into a semi-mist, and the water in the oil is rapidly evaporated into water vapor and continuously sucked into the condenser by the vacuum pump. The water vapor entering the condenser is cooled and then returned to the original water for release. The oil in the vacuum heating tank is discharged into the fine filter by the oil discharge pump, and the particulate impurities are filtered out through the oil filter paper or the filter element, thereby completing the vacuum oil filter quickly. Remove the impurities, water and gas from the oil, so that the clean oil is discharged from the oil outlet.