Send the disposed raw material oil and catalyst respectively to sealed melting furnace. Due to heatstroke and effect of special catalyst, raw material waste oil is changed to gas from pasty substance. Gas molecules incurring are increasing along with rising temperature in the furnace. As gas molecules are moving nonstop, mutual collision occurs between molecules, between molecule and wall, and molecule and catalysts in the reaction still at the entrance. A small portion of smaller molecules enter flown line via splitting of catalysts before becoming refined oil product via separation, cooling and filtering; and the other part of bigger molecules return to the gasifying melting pot for reaction till all are dissociated to qualifying petroleum products with the help of catalyst.