In the known oil and gas field of the Dagang oilfield,there exist very good anomaly demonstrations over all targets of geochemical exploration.It is proved that geochmical prospecting can catch true geochemical information reflecting oil and gas fields,and is very effective in looking for and locating oil gas fields and determining their sizes.According to anomaly characteristics,this paper has summed up the geochemical anomaly model for the Dagang oilfield.It provides geochemical basis for the development of geochemical prospecting work.