Abstract:Based on correlations between current organic carbon concentrations, sediment concentrations(CTSS) and runoff depth(Q), the estimating models for particulate organic carbon concentrations(CPOC)and dissolved organic carbon concentrations (CTSS)in Beijiang River Drainage, Guangdong Province were reconstructed as CPOC=0.0195×CTSS+0.0589 and CDOC = 0.0047×CTSS+0.0027×Q+0.9087, respectively. The results of organic carbon reconstruction indicated that the major form of organic carbon in Beijiang River Drainage was POC. For intra-annual distribution, the concentrations of DOC and POC in all hydrological stations investigated were the highest in flood period. Downward trends were detected in general for inter-annual dynamics. For spatial distribution, the concentrations of DOC and POC decreased from upper reaches to lower reaches except for Sanshui where the concentrations of DOC and POC started to increase.