Abstract: Xi'an ground fissure is a typical geo-hazard with nearly half century and even active up to date.Based on the theory of deformation decorrelation of the active ground fissures,we mainly investigates the positioning method of active ground fissures by analyzing the pseudo-coherence map of adaptively filtered differential interferogram.The manual and automatic methods are also deduced to extract the active fissure information from pseudo-coherence map.This method is tested by two real ERS SAR data sets,and the feasibilities can be well verified.In conclusion,on the one hand,the pseudo-coherence map can be applied to extract the position of active fissures,and to monitor the temporal evolution of ground fissure on the other hand,it can be used to detect the unwrapping error.