Abstract: The paper describes the regional geology and geochemistry of the Dehelongwa Cu-Au deposit and analyzes the ore-forming conditions.Comprehensive anomalies of elements such as Au, Cu, Ag, Pb and Zn were discovered in a 1/5,000 secondary halo reconnaissance.The secondary halo abnormities reflect the existence of Cu-Au mineralization, and Au, Cu, Ag, Pb and Zn are the important indicator elements .The abnormities are closely related with the mineralization forms and occurrences controlled by the faulted structures, further illustrating  that the copper-gold ore in this area is mainly fault-controlled.

Key words: Secondary halo, Abnormal, Structure, Dehelongwa, Cu-Au deposit