Abstract: There are lots of theories about the causation of ground fissures inXi'an,such as the tectonics theory, the excessive groundwater exploitation theory and the compositive theory. Based on the construction of the geologic environment monitoring network in Guanzhong urban agglomeration, the latest survey of Yuhuazhai ground fissures and land subsidence in Xi'an suggests that the extensive piping and quick sand in self-supply wells is a factor to induce ground fissures and the land subsidence. The paper works out the higher hydraulic gradient seepage deformation which can lead to sand gushing and the part of aquifer deformation into the composite aquifer is the main factor to induce ground fissures and the land subsidence. The paper also makes a systematic summarization of development characteristics of ground fissures and land subsidence by seepage deformation. The results will supply new schemes and methods for the causation of the land subsidence and ground fissure sin Xi'an and laid out a clear roadmap of control measures to the land subsidence and ground fissures.