Groundwater is the main source for water supply in Beijing-Tianjin-Hebei Plain. Groundwater resource and geological environment have been influenced by human activities and climate change. Groundwater dynamic is a direct response to human and climate,so the groundwater level changes in different special scales for a long time span were analyzed by the method of numerical simulation based on the hydrogeological settings and observation wells data. Moreover,the groundwater dynamic mechanism was revealed. Results suggest that groundwater level had declined continuously with a rate of 0.36m/a. Large shallow groundwater cones of depression had also formed,among which Shijiazhuang cone groundwater level declined the fastest with the rate of 1.1m/a. The renewability of groundwater changed obviously with mean annual recharge rate during 2001 ~ 2010 (154.97mm/a),decreased by 6.2% compared with that in 1961 ~ 1970. The exploitation rate was exceeding the precipitation recharge rate which caused the groundwater level declined in different special scales. Exploitation was the main factor for groundwater dynamic while precipitation was the limiting factor for groundwater renewability. Water supply will face challenges for Beijing-Tianjin-Hebei Plain in the future.