Migration, accumulation and micro-leakage effects of oil and gas will lead to changes of the geochemical environment and the concentration of trace elements which are closely related to organic matter in the top of soil. Data of multi-objective regional geochemical survey will provide the regional geochemical information. Based on using multi-target regional geochemical data obtained from southern Songnen Plain, in combination with the abnormal results of the trace elements which are related to known oil and gas fields, the authors have detected that there exists response relationship between such indicators of trace elements as Cl, S, I, Sr, CaO, TC and Br and oil and gas fields, and hence these indicators are effective indexes in oil and gas prognosis.