Vegetable oil heated repeatedly at a high temperature was detected with threedimensional fluorescence spectra. The method can obtain the threedimensional fluorescence spectrum of the sample quickly and accurately. However, it is just a qualitative analysis. When the fluorescence intensity changes a little，it may lead to  incorrect or missing discrimination . The spectral information of vegetable oil samples was analyzed with threedimensional fluorescence spectra, and then lifetime of the photons in it was calculated with fluorescence lifetime analysis, it could be identified whether the oil was heated repeatedly at high temperature with the fluorescence lifetime of different oil samples. The combination of the two methods improves the detection accuracy, so it can help to solve the problems of false detection, and missing detection, so as to provide a strong reference for the detection of vegetable oil heated at a high temperature.