Exemplified by some results obtained from the electric imaging detection of active faults in Zibo City, this paper described the method for geological interpretation and analysis of images from the electric imaging technique, and studied the input impedance range of the instrument for urban active fault detection as well as some problems which deserve attention in data processing and inversion. With three typical electric imaging profiles that control the Zhangdian-Renhe fault system as examples, the authors inferred positions of the concealed faults and verified the correctness of electric imaging results through drilling. It is thus concluded that the electric imaging method can obviously play a very important role in the detection of urban active faults.