Abstract: Objective To describe the morphological feature of bio-waste oil in Raman spectrum for the discrimination of bio-waste oil from edible vegetable oil.Methods The morphology and difference in Raman spectrum for bio-waste oil and edible vegetable oil were compared and analyzed.Results In the full- and extended-range Raman spectra at the wavelength of 532 nm,there was a morphological feature of smooth bulk peak for various bio-waste oil samples which was not observed in all the samples of edible vegetable oil.The peaks of bio-waste oil samples in the first-derivative extended-range spectrum could be effectively distinguished form those of edible vegetable oil samples and the difference in the first-derivative full-range spectrum between the bio-waste oil and edible vegetable oil could be used to quantify the amount of adulterated bio-waste oil in vegetable oil.Conclusion A smooth bulk peak in Raman spectrum exists universally in the detection of various bio-waste oil samples and could be used in the detection of adulterated bio-waste oil in edible vegetable oil.