Abstract: According to the field observation data concerning the Jiaojiang River estuary, the characteristics of the spatial distributions of longitudinal and vertical directions and the temporal distributions of the seasons and tide are analyzed in this study. Based on the relative strength between the runoff and tidal current, the Jiaojiang River estuary is divided into three segments. The analysis results indicate that: (1) The influences on the spatial and temporal distribution of the sediment concentration is given by the runoff and tide scouring the riverbed and transporting the sediment; (2) The vertical gradient of the sediment concentration is larger in the segment controlled mainly by the runoff than that in which controlled by the tidal current. There are significant differences among the moments of the peak sediment concentration in the different segments. The change periods of the sediment concentration are about 6 hours or 12 hours. The differences between three segments are mainly caused by the main direction of sediment transportation, the hydraulic activity and the sediment sources; (3) The increasing runoff discharge can raise the riverbed erosion rate and make dilution of effects on the sediment concentration; (4) The flood can break the rules of the sediment distribution and reduce the sediment concentration severely for a long time. The analysis results would be of important scientific values revealing the sediment movement rules in the estuaries and be of realistic significance for estuary regulation and resource utilization.