To evaluate the extent of water pollution, variable methods are available in measuring chemical oxygen demand (COD) , dissolved oxygen ( DO) and biochemical oxygen demand ) BOD) . The BOD 5 measuring, as a standard method, requires a long time to complete the measurement. In search for more convenient method, this report dealt with the possibility of the new measuring method with yeast extract. Sewage treated with activated sludge, farm drainages, river water, sewage from factory of chicken meat, and four sorts of chemicals