The calculation model of the spatial distribution of water vapor pressure in Chongqing in real terrain is established on the basis of conventional meteorological data. The monthly and the annual mean spatial distributions of water vapor pressure in over Chongqing are calculated and the map drawing and particularly the spatial distribution of water vapor pressure over Chongqing in real terrain are completed. The analysis shows that water vapor pressure decreased with the increasing of sea level elevation; the minimums of water vapor pressure for all months appeared in the northeastern mountainous area; there is distinct seasonal change in water vapor pressure over Chongqing.