In the northern Wancheng fault zone,the surface conditions are complex,seismic and drilling operations are difficult,and the oil and gas enrichment is still unclear. Therefore,by using the microbial oil prospecting method with the minimum cost and the highest efficiency,the oil and gas prospects and enrichment in this area are determined.Methods:The study area is approximately 230.0 km2,the sampling interval of N-S 500 m× W-E 250 m is properly densified in some areas perpendicular to the Wancheng fault zone and structurally favorable zones,and 2354 samples are collected. Results: For each sample,gas and oil indicator bacteria were analyzed respectively,that is,the microbial abnormal value of the oil and gas in the study area.The microbial anomalies are mainly distributed in the eastern Wancheng fault zone,in which microbial gas anomalies are scattered and weak,and there is no independent gas reservoir.Conclusions: On the basis of comprehensive geological and other data,the distribution of microbial anomalies indicates that the Wancheng fault zone shows two-way provenance from the northwest and northeast directions,and the oil and gas come from the Meihuaiqiao sub-sag,which is a near-source accumulation area.The eastern side of the Wancheng fault zone and the lowstand fan sand body in the slope-break zone are favorable oil and gas enrichment areas with good prospects and are mainly composed of the Neogene Xingouzui Formation reservoir.There is a small oil reservoir in the western Wancheng fault zone that may have formed in the Cretaceous. Finally,the classification and evaluation of abnormal microbial zones are carried out,and the key research areas,evaluation favorable and less favorable areas are pointed out,which has great social and economic benefits and far-reaching practical significance to greatly reduce the exploration risk and improve the exploration success rate.