Abstract: This review reports the progress of oil-based unsaturated polyester resins(UPR) in the last two decades, including plant oil resins cured via direct polymerization, traditional oil-based UPR, oil-based unsaturated ester resins, blending oil-based UPR, styrene-replacing oil-based UPR, etc. At last, the prospect of the oil-based UPR is described.