Abstract: Oxygen consuming pollution in inland waters not only directly impacts the balance and stability of aquatic ecosystems but also plays a crucial role in fluvial carbon transport and regional carbon cycle. In response to the increasingly pronounced oxygen-consuming pollution in Dongjiang Lake basin and its potential influence on regional carbon cycling, this study utilized monitoring data from 2015 to 2024 to systematically analyze the spatiotemporal variations in dissolved oxygen (DO) and major oxygen-consuming pollutants over the past decade. Furthermore, we quantitatively assessed the fluvial export of dissolved organic carbon (DOC) from the basin and its role in the regional carbon budget. The results showed that the DO, permanganate index (COD_Mn), five-day biochemical oxygen demand (BOD₅), and ammonia nitrogen (NH₃-N) concentrations in the basin ranged from 4.1 to 11.7, 0.2 to 4.3, 0.1 to 3.9, and 0.01 to 0.92 mg/L, respectively. Overall, oxygen-consuming pollution remained stable but posed a risk of exceeding standards. The concentrations of oxygen-consuming substances in inflow rivers exhibited a general decreasing trend, while the concentrations within the lake exhibited little variation or even an increase, revealing the potential risk of endogenous contributions. Generally, temperature was the primary driver of seasonal fluctuations in DO, while the influence of oxygen-consuming substances varied among different sections. The DOC export from the basin ranged from 453.7 to 1353.4 t C/year, offsetting 0.1% to 0.3% of the net ecosystem productivity (NEP) within the basin, significantly below global average. This study highlights the temperature-driven evolution of DO, the spatial variability of oxygen-consuming substance impacts within the watershed, and the role of DOC export in the regional carbon budget, providing scientific evidence for the basin-scale control of oxygen-consuming pollution and carbon management strategies.