Abstract: Based on time series sediment trap samples collected in the southern Sri Lanka of the central equatorial Indian Ocean from January to December 2020, we measured the magnitude of total sinking particle and particulate organic carbon (POC) fluxes, and evaluated the impact of upper ocean physical processes on sinking particle fluxes in combination with remote sensing physical parameters, numerical model and reanalysis data. Results showed significant seasonal variations in total sinking particle and POC fluxes ranged from 4.57 to 35.75 mg/(m²·d)［(18.94 ± 10.18) mg/(m²·d)］ and 0.27 to 2.97 mg/(m²·d)［(1.09 ± 0.66) mg/(m²·d)］, respectively. Overall, three discrete high-flux events occurred in periods of January to March, June and September to November. The coupling regulation of surface mixing and thermocline fluctuation was supposed to responsible for the variability in fluxes. While the development of Southwest Monsoon Current and equatorial Wyrtki Jet may also depress the biological carbon pump due to the deepening effect on the thermocline/nutricline depth.