Abstract: The characteristic of n-alkane distributions of 8 kinds of marine fuel, 8 kinds of Middle East crude oil and 13 kinds of non-Middle East crude oil were analyzed by GC-FID.The diagnostic ratios with the geochemical significance and the strong anti-weathering such as n-C₁₇/Pr, n-C₁₈/Ph, Pr/Ph, LMW/HMW, CPI and (n-C₁₉+n-C₂₀)/(n-C₁₉~n-C₂₂) were used as modeling parameters, Fisher discriminant of these 29 kinds of oils were performed.Since n-C₁₇/Pr and n-C₁₈/Ph were collinear and n-C₁₇/Pr of marine fuel had obviously changes during weathering, n-C₁₇/Pr cannot be used as a modeling parameter.The Wilks's lambda distribution of modeling corresponded to P value of 0, which indicated the discriminant model was valid, and the identification accuracy of model was 93.1%.The identification accuracy of oils after short-term weathering for 30 days could also reach 93.1%, this meant that the established model was also applicable to identification of weathered oil spills.