Abstract: In order to research the influence of Yellow River Sanmenxia reservoir area sediment to COD, this paper takes water from Sanmenxia Baxia, Tongguan, Longmen three sections, and obeys the rules to prepare clear, clear and silting and silting water samples. It tests the same water with acid, the clear and silting water and clear with same water sample, the COD values of water, clear and silting water, clear water with sediment concentration more than 3kg/m3. The conclusion is that 1. Use CODcr test to show the water organic pollution degree in the Sanmenxia reservoir area Yellow River tributary and dry season main stream; 2. The clear water CODcr can show the water quality organic pollution situation typically to the water with sediment concentration more than 3kg/m³.