Abstract: The Xihu Sag is the largest offshore oil-gas basin in China, with complicated reservoir fluid properties which are difficult to identify quickly. Based on a large number of three-dimensional quantitative fluorescence spectrum data, through carrying out the analysis of key parameters, it is found that the intersection characteristics of key parameters, such as the excitation wavelength, emission wavelength, fluorescence contrast level, oil index and so on, have obvious correlation with the reservoir fluid properties. Hence, based on the measured data of 15 exploration wells, combined with the logging and testing results, interpretation charts and standards of reservoir fluid properties in the different zones of the Xihu Sag are established, that is, the intersection interpretation method of three-dimensional quantitative fluorescence key parameters. This method is simple and rapid in data acquisition, and can quickly identify the fluid properties of difficult reservoirs such as high resistivity water layer and low resistivity gas layer, and it is not affected by the physical properties of the reservoir. The evaluation results are consistent with the well logging and testing results, and it has successful application in the field, the technology is worth promoting.