Abstract: The main exploration activities in the East China Sea Basin are concentrated in the Xihu Sag and Lishui Sag. Various types of reservoirs, such as oil reservoirs, gas reservoirs, and CO₂ reservoirs, have been discovered in the basin. The reservoir fluids are complex, making it difficult to identify their properties quickly. By analysing a large number of 3D quantitative fluorescence spectrum characteristics and key parameters of more than 60 explorational wells in the basin, it was found that the intersection characteristics of the two key parameters: fluorescence contrast level and oil index are significantly related to the reservoir fluid properties. Based on the results of well logging and well tests, this paper establishes the interpretation diagram and interpretation table of reservoir fluid properties in different blocks of the East China Sea Basin. This method is convenient for obtaining on-site data. It can not only quickly identify conventional petroleum reservoirs and aquifers, but also efficiently and accurately identify complex fluid properties such as high-resistivity aquifers, low-resistivity gas reservoirs, and low-permeability gas reservoirs. The evaluation results are consistent with well logging and test results. This method has been applied successfully during well drilling processes and is worth promoting.