The refining of industrial waste lubricating oil was investigated with N-methyl-2-pyrrolidone (NMP) and Duo-solvent (ethanolamine and NMP) as solvents, respectively. The preferred refining process is duo-solvent refining under 70 ℃ with 5% ethanolamine, under these conditions the total oil yield was 89.85%. The physical properties of recycled oil is listed as follows: viscosity（40 ℃） 30.89 mm ²•s ^-1, viscosity（100 ℃） 5.6 mm ²•s ^-1, viscosity index 120.4, refractive index 1.450, Color 2.0, freezing point -28.8 ℃, flash point 219.6 ℃ and sulfur content 0.057%.