Abstract: Spectra, salinity, total suspended solids and colored dissolved organic matter are sampled at 44 locations in the Pearl River estuary on December 18, 19 and 21, 2006. The samples are analyzed. Based on the experimental results, the relationship between the absorption coefficient of chromophoric dissolved organic matter (CDOM; g₄₀₀) and the remote sensing reflectance is obtained. In the Modaomen waterway, the result shows that there is a strong positive linear relationship between the in-situ reflectance ratio (R₇₀₄/R₅₁₃) and g₄₀₀ (R²=0.7, P<0.001); and in the Humen waterway, a negative linear relationship between the in-situ reflectance ratio (R₇₀₃/R₄₈₈) and g₄₀₀ (R²=0.58, P<0.001) is found. Additionally, the absorption coefficient of CDOM and the salinity in the two waterways are studied, and the two parameters are highly correlated (R²>0.67). Finally, using the result of this study, a novel method is developed to monitor the surface salinity distribution in estuarine waters. The new method is validated using the simulated Medium Resolution Imaging Spectrometer Instrument (MERIS) data with satisfactory results. The study demonstrates that the salinity variation in the Pearl River estuary (E_RMS<0.308%) can be monitored by remote sensing techniques (e.g., MERIS).