In-Situ Suspended Particulate Matter(SPM) concentration of the water column and particle size distribution above the middle layer and bottom layer were measured in the Taean-Haean National Park, West Coast of Korea. The short-term series of in-situ suspended particulate matter concentration, total volume concentration, beam attenuation coefficient, mean grain size, floc size and distribution have been ensemble averaged according to tidal variation. Time variation of in-situ particle size and concentration shows bottom layer supplies relatively fine-grained particles with compared to middle layer. This explains a good correlation between sediment concentration and beam attenuation coefficient due to well defined, monotonous size distribution. Abundance of small microfloc and large macroflos with time and water column size distribution indicated the difference between organic matter in marine snow of turbidity maximum near-bottom layer and fine grain primary particles of water column. The particles supplied toward lower water column from upper water column during low tide showed a multi-modal distribution with two-three peak at coarse fraction, possibly due to the resuspension and the flocculation associated with marine biological activity and the increased shear velocity at near bottom, break-up of large flocs. This study can be used qualitative and quantitative analysis of in-situ fine suspended sediment distribution, resuspension and flocculation, land(fresh water) and marine(sea water) based source of suspended particulate matters, according to marine environmental relationship and global climate change.