Abstract: The standard curves of relations of actual value and measured value are established based on transformer oils with different hydrocarbon compositions to investigate the different measured results of antioxidant content in the oils. The results show that the measured values change with aromatic content and the detection deviation is largely depends on the aromatic content in oils. To optimize the measuring method, low aromatic content base oil (CA value 0.23%) is used to establish calibration curves for detecting antioxidant content of samples. The correction factors and the modifier formula are established to calculate the correct value. The deviation between the correct value and the theoretical value is less than 0.005 point. The optimization greatly improves the accuracy of the detection method.