Studies on the transport mechanisms and behaviors of six trace metals (Fe, Mn, Cd, Cu, Pb and Zn) in the Tsengwen river and estuary were performed for the high-flow and low-flow seasons. Dissolved metals in the Tsengwen river are slightly higher than those in the pristine rivers but much lower than those in the heavily polluted rivers of the world. The riverborne dissolved Fe, Mn, Cu, Pb and Cd, however, this was likely controlled by the mixing process in the estuary. Particulate and sediment metals, similar to dissolved metals, showed elevated concentrations in the middle river, but there was little difference throughout estuarine locations. The enriched levels of particulate and sediment metals with reference to backgrounds (shale's metals) were found in a sequence of Pb, Cd > Zn, Cu > Fe, Mn.