There might exist large scale geo-vacuum zones in the earth’s crust. Almost all destructive great earthquakes in China during history resulted in significantly extensive subsidence that could only reasonably be attributed to the existence of geo-vacuum zones in the crust. A geo-vacuum zone was basically characterized to be under a situation of lower vertical pressure than the theoretic hydrostatic pressure at the depth. Such vertical pressure decrease was induced by tectonic movements and might produce dilatancy of the rocks. Discoveries in the super-deep drilling well in the Kola Peninsula further confirmed the existence of such phenomena. Generally speaking, such geo-vacuum zones could be located and studied by investigating low velocity zones in the crust and synthesizing the data of geophysical survey. Geological evidence and implications, such as stratigraphic records of earthquake, lithological evidence and implication of fissure in oil-gas exploration, were discussed in the paper. In addition, the mechanism of geo-vacuum zone’s formation was briefly discussed in the paper.