The application of the mathematic statistics in the forecast of groundwater regime in the areas, where the groundwater is influenced by some factors, shows its good efficiency. The study on monitoring data obtained from January 1995 to December 2000 in the Tr¶ng Bµng area, T©y Ninh province has been showing the linear correlation between the groundwater and rainfall with the correlation coefficient R= 75%. Basing on this correlation we can forecast the change of water level in the aquifer qp when there is the change in rainfall and evaporation.