The reservoir heterogeneity of karst shoal facies in the second member of Dengying Formation on the northern slope of central Sichuan paleouplift on the east side of Cambrian-Sinian Aulacogen in the Sichuan Basin is strong, and the main controlling factors are complex, which become the key factors restricting the next step of targets optimization of natural gas exploration in the northern slope area. Using 3D seismic data and based on the latest exploration well drilling, logging and other data, innovative ideas were proposed to depict favorable area of beach facies reservoir using the karst landform of the lateral sedimentary period of Dengying Formation. The overlying strata, Canglang Formation, was used as the reference layer, and micro paleogeomorphic analysis was carried out using the impression method to characterize the geomorphic characteristics of Dengying Formation during the karst period. On this basis, the seismic response characteristics of the reservoir were carefully studied, and a seismic facies classification model was established. The waveform classification method was used to predict favorable areas for the development of karst shoal facies reservoirs. The results reveal that the development pattern of the karst shoal facies reservoir in the second member of Deng Formation follows a northwest to southeast direction similar to the distribution direction of the aulacogen, which is consistent with actual drilling and geological understanding. Compared to the conventional residual thickness method, this method takes more into account sedimentary characteristics and geological laws, the multiplicity of predictions is reduced, the semi-quantitative prediction can be achieved, and the favorable guidance for studying favorable areas for the development of karst shoal facies reservoirs in the context of monoclinic structures on the northern slope of paleouplifts is thus provided.