Abstract: The action and effect of groundwater on engineering projects and their environments are increasingly apparent and more deeply known in the practice.The problem is not a pure hydrogeological subject. It is essentially a problem concerning with hydrogeology and engineering geology and is called temporally engineering-hydrogeolgical problem, which is found in the process of engineering construction and in study of environmental geology and expresses various engineering geological and hydrogeological problems due to the action of groundwater. In order to complete deciphering the problem, it is illustrated by the examples of interactions between water and rock, bedrock pit discharge and sand flow by crypto-erosion, foundation subsidence and loess subsidence, frozen damage of road surface and tunnel water burst, mining pitout burst and shaft failure, dam basement leakage and stability, slide-stable dam basement, and geological hazards due to groundwater. The purpose of the paper is to indicate a direction which is worthy to be studied and must be highly emphasized.