The aim of this study is to develop a rapid offshore eutrophication assessment technique by parallel factor analysis (PARAFAC) and partial least squares regression (PLSR) based on fluorescence excitation-emission matrix spectroscopy (EEMs) of chromophoric dissolved organic matter (CDOM), UV-visible spectroscopy of CDOM, dissolved oxygen (DO), chlorophyll a (Chl a) and turbidity (Tur). EEM-PARAFAC model identifies three fluorescent components, two humic-like (C1 and C2) and one protein-like (C3). a220, a254, a270, a350, C1, C2, C3, DO, Chl a and Tur are selected to study their correlations with total phosphorus (TP) and total nitrogen (TN). Using trophic index (TRIX) as the reference, the model for rapidly evaluating eutrophication status is developed by PLSR. The correlation coefficients of the PLSR model are 0.9721 for the training data and 0.9827 for the validation data，and the classification accuracy is 89.0% for the validation data. The results prove that optical parameters of CDOM can be as substitutes for TP and TN in rapid assessment of offshore eutrophication.