Collecting Sediments of ditches in three land-use types in order to measure the content of dissolved organic carbon (DOC),we researched on the content and distribution of sediment DOC under three land-use types in Sanjiang Plain.Furthermore,we discussed the influence of three land-use types on sediment DOC. The findings indicated that the content and distribution of sediment DOC changed obviously with changing of land use type in Sanjiang Plain,though they were excavated for drainage on the wetlands.The wetland was reclaimed for the farmland,which benefited the accumulation of sediment DOC for ditches,at the same time, compared with paddy field,the dry land was favorable to the accumulation of per layer of sediment DOC for ditches;The vertical distribution of sediment DOC for ditches obviously changed in three land use types, what's more,compared with thread-type ditches,the vertical distribution of sediment DOC in edge-type dit- ches demonstrated better characteristics of deposition;The land cultivation and drainage were the main cause of the different content and distribution of sediment DOC in all kinds of ditches.The land cultivation and drainage not only led to transference and sedimentation of DOC,but also the difference of sediment DOC con- tent and distribution in the ditches.