The study on distribution of freshwater bivalves in relation to bottom sediments was carried out based on 16 sampling stations of the Han-river and the Kum-river in September, 1986. In the type of bottom sediments, the stations with rapid current are composed of coarser sediment than the ones with relatively slow current. The bivalves were identified by 11 species belong to 3 families. The distribution of some freshwater species were limited by the type of bottom sediment. For example, two species of them, Solenaia triangularis and Limnoperna fortunei were only found on rocky substrates or large stones community like boulder. Cristaria plicata was dominant on typical muddy community and Lamprotula leai on sandy or sandy gravelly community. And L. coreana collected on sandy bottom was the only species which wasn`t presented in the Han-river. Distribution pattern of other species might be more influenced on other environmental factors of water mass than bottom sediment. This study could be explained that the composition of bottom sediments by result of water movement and water quality would have an effect on the distribution of freshwater bivalves.