Identification of oil varieties play an important role in environmental monitoring,accident identification and other fields.Based on the complex composition of oil products,the fluorescence lifetime imaging technique combined with nonlinear least square method was proposed to fit the fluorescence life attenuation curve and extract mean fluorescence lifetime parameters,and thus solved the classification and identification problem of different oil mixtures.Using time-resolved fluorescence experiment in laser-induced fluorescence system,the best fitting curve was determined from the correlation index and residual distribution.Experimental results show that the fluorescence life attenuation curves of three different oil products had different fitting effect according to different exponential attenuation curves.The optimal fitting curves were selected to fit the average fluorescence life parameters of different oil products according to the synthesis method,and trustiness of the results was above 95%.Taking the average fluorescence life of all excited pixels as the center,using 2 times standard deviations as the confidence limit,the probability of pixel fluorescence lifetime value falling within their confidence intervals in two different oil excitation regions was calculated as 87% and 68%,respectively.Comparing the mixture of three different oil products,the possibility of using fluorescence life analysis to identify different oil type was verified,and the spatial distribution information of different oil types was determined by fluorescence life imaging.Fluorescence life analysis provides a new approach for oil product identification,component analysis and spatial distribution detection.