Based on the solar radiation observations from CE318 sunphotometer at the 936 nm channel，the improved Langley technique is used to retrieve the atmospheric column water vapor content over Zhengzhou. The empirical expression of the relation between atmospheric column water vapor content and ground water vapor pressure is derived. The calculating results show that the seasonal variation of the atmospheric column water vapor content was the greatest in summer, the second in autumn, and the least in winter. The diurnal evolution shows that there is a lower value in morning and evening, and higher value appear around noon. There is a good linear relationship between atmospheric column water vapor content and ground water vapor pressure.