Abstract: Oxygen consumption and permanganate index were measured by the standard GB/T5750.7-2006, GB11892-1989.Although the two method principle and test procedures were basically same, two methods of calculating formula of concentration annotations were not consistent.Through the method validation, it was proved that the concentration in the calculation formula of oxygen consumption marked for concentration of potassium permanganate standard solution in the standard GB/T5750.7-2006 was wrong, it should be labeled as sodium oxalate standard solution concentration.