In order to investigate the sediment dynamics behavior of Tirumalairajan river estuary characterized by sediment sampling were undertaken to obtain data sets of grain size parameters in monsoon and summer seasons (2009). The mean grain size increased, sorting improved, and skewness became more positive and leptokurtic to very leptokurtic nature in both seasons. The spatial distribution indicates majority of sample fall in sand category in both seasons. Based on the CM pattern the sediment fall in rolling and suspension field. The sediments may be derived from offshore and catchment area deposits of the clay and silt, and evidence was found to suggest that these deposits are being eroded by tidal currents.