Auroral intensity ratios at Zhongshan Station in Antarctica on 8 April 1999 are studied, along with variations in penetrated electron energy. Ratios of I (557.7 nm)/ I (427.8 nm) during the quiet period were from 5 to 22, and I (630.0 nm) / I (427.8 nm) ranged from 1 to 2.76. These variations were not caused by changes of atomic oxygen concentration, but rather by penetrated electron energy variability, or other mechanisms. Ratios decreased sharply during the auroral substorm, ranging from 1.66-6.5 and 0.071-1, respectively, mainly because of the increase in penetrated electron energy. At the onset of the substorm, the ratios reached their minima. This means that penetrated electron energy was maximized. When the substorm weakened, the penetrated electron energy returned to the pre-substorm level. Auroral intensity ratios at Zhongshan Station in Antarctica on April April 1999 were studied along with variations in penetrated electron energy. Ratios of I (557.7 nm) / I (427.8 nm) during the quiet period were from 5 to 22, and I (630.0 Ratios decreased sharply during the auroral substorm, ranging from 1.66- 6.5 and 0.071-1, respectively, mainly because of the increase in penetrated electron energy. At the onset of the substorm, the ratios reached their minima. This means that penetrated electron energy was maximized. When the substorm weakened, the penetrated electron energy returned to the pre-substorm level.