Abstract: The responses of spectral signature to suspended sediment concentration(SSC) of turbid waters in the Huanghe estuary are addressed based upon in situ above-water radiance measurement and water sampling,for suspended sediment concentration ranging from 5.4 to 1 713.1 mg/L.The influences of suspended organic particle matter and particle distribution of suspended sediment on spectral signature are analyzed.Some empirical relationships between remote-sensing reflectance in Landsat TM bands and suspended sediment concentration are established.The best correlation is obtained for the reflectance ratio of Landsat TM3 and TM2,which is further applied to the estimation of SSC in the estuary.