Hanjiang River delta (including Hanjiang, Rongjiang, and Lianjiang) is among the six largest deltas in Chinese coastal areas, yet little is known about the estuarine chemistry of biogenic elements in this subtropical estuary. The sources, distribution, and estuarine behavior of nutrients, and chromophoric dissolved organic matter (CDOM) in the Hanjiang River Estuary (HRE) were investigated during the summer of 2010. The trajectory and sectional distribution of water temperature and salinity showed strong stratification accompanying with the north and south plumes in the HRE during summer. Nitrate, dissolved inorganic nitrogen (DIN), and dissolved silicate (DSi) showed conservative mixing behaviors along with absorption coefficient a₃₅₀ and humic-like fluorescence components. Reactive phosphate, nitrite, ammonium, and protein-like components fluctuated with salinity. The effective DSi concentrations of freshwater end-member in the north plume were higher than that in the south plume, indicating that silicate weathering was stronger in the Hanjiang basin than in the Rongjiang/Lianjiang basins. The higher effective concentrations of a₃₅₀ and humus-like fluorescence in the north plume than in the downstream Hanjiang River suggested their additions in the low salinity area of the estuary. The Hanjiang River showed a typical high fluvial DSi: DIN ratio (1.9) and low CDOM concentration compared with other southeast Chinese rivers, suggesting relatively small anthropogenic perturbation. Therefore, the HRE showed potential phosphorus-limitation for phytoplankton growth.