Concealed faults constitute a latent threat to the city, and the application of geochemical method to surveying concealed faults has already become a relatively mature means. Nevertheless, the urban environment is rather complex, and the disturbance factors are numerous, which increases the detection difficulty. The authors determined the threshold of the anomaly through the surveying work in the experimental area, and raised the anomaly reliability through a series of quality guarantee mechanisms. The effective anomalous spots reach 82% in the geochemical survey, and there exists fairly high consistency between the inferred faults and the broken points detected by shallow seismic prospecting.