The experimental part of the experiment was divided into two parts, countercurrent extraction and white clay supplementation. The refined oil obtained by countercurrent extraction is called raffinate oil, and the raffinate oil is refined with white clay and then the refined oil is called white earth oil. Extraction tests were carried out in our glass extraction tower. After the raw materials were extracted by two stages, the removal rate of total sulfur, total nitrogen, and alkali nitrogen in the refined oil decreased with increasing solvent ratio. After the second-stage refined oil was re-purified with white clay, the removal rate of alkali nitrogen reached more than 50%, and the rotating oxygen bomb reached 134 min and 165 min, respectively, reaching the requirement that the MVI900 (or 90 BS) base oil should not be less than 130 min for rotating oxygen bombs. After the raw materials were denitrogenated-clay-refined, the removal rate of alkali nitrogen was 81.8%, and that of rotating oxygen bombs was 130 minutes. This shows that only some of the basic nitrides, but not all basic nitrogen, affect the sensitivity of the base oil to T501. Chemicals. If it is supplemented and refined with white clay, the rotating oxygen bomb can reach more than 200 minutes to meet the MVIS base oil standard requirement. The minus three-wire denitrification-white clay oil has the characteristics of low alkali nitrogen content and high fraction of rotating oxygen bombs, but the viscosity index does not change. The adoption of a new two-stage furfural refining process can improve the oxidation stability of our heavy base oil and allow it to reach the MVI base oil standard, which solves the bottleneck problem that has plagued our company's heavy oil production. The process used in the treatment of reduced three-wire dewaxed oil shows that the oxidation stability of refined oil after two-stage solvent extraction can meet the MVI base oil standard. If it is supplemented and refined by white clay, then the rotary oxygen bomb can reach more than 200 minutes, which meets the MVIS base oil standard requirement. This process does not require denitrification, and there is no problem that the denitrification acid slag is difficult to handle. The extraction process can be directly used in the production of the factory's heavy-duty furfural device, without adding new equipment, just add a few lines can be small. Since the extracted oil obtained by this process contains no wax, the condensation point is low, and the content of aromatic hydrocarbons is high, it can be used to produce products with high added value such as rubber-filled oil.