The active pictures of XGF (Xi'an Ground Fissures) are given and analysed. Both tectonic characteristics and artificial characteristics of XGF are shown. The tectonic control functions on XGF appear not only geometrical but also mechanical, the former can be seen from space distribution feature and geometrical pattern of XGF, the latter can be seen from its formation process, as well as the time feature of earthquakes and XGF. The human activities, mainly overextraction of piezometrie ground water, result in land subsidence in Xi'an. The ununiform land subsidence is responsible for high rate of the movement of XGF, which is about ten times higher than the rate of tectonic movement. According to the major rate(the rate of vertical slip), XGF is classified into three grades. The map of XGF classification well reflects its multiplicate cause mechanism.