Based on an integrated study of geochemical data obtained in southern Songliao basin in the past 20 years, this paper has given a rough description of the oil and gas micropercolation and origin of geochemical anomalies in this area, the main factors affecting surface geochemical exploration, the effectiveness of geochemical indices, the technique for extracting anomaly information, and the model of geochemical anomalies, and summed up the effective oil and gas geochemical technical series suitable for this area, and a suite of techniques for elimination of interference, extraction of anomaly information and interpreation and appraisal of geochemical anomalies.