Given a series of problems such as unplanned shutdown and flight failure caused by the fuel contamination of aviation engine lubricating oil, it is necessary to monitor the lubricating oil in use to determine the right time to change all lubricating oil. In this paper, Spectrum Two infrared spectrometer and Spectrum Quant software of PerkinElmer Company in the United States were combined with the American Society for Materials and Testing Standard (ASTM-E2412-10) on the monitoring instructions of synthetic ester lubricants. The fuel contamination degree of Mobil Jet Oil Ⅱ lubricating oil was quantitatively analyzed. The standard working curve of fuel contamination concentration and peak area of 815~805 cm^-1 spectral region was established by using the two-point baseline area method. The correlation of the working curve was 0.999 6, and the standard prediction error was 0.544 1. The standard deviations of the five groups of repeated tests were all lower than 0.12%, which indicated that this method had high prediction accuracy and good repeatability. At the same time, the same lubricating oil samples were detected using the working curve and the fuel sniffer of Spectro Scientific company, and the results were similar, which indicated that the established quantitative working curve could meet the monitoring requirements of fuel contaminationin lubricating oil in civil aviation.