Abstract: The central anticlinal belt of the Xihu Sag hosts extensive large-scale, high-angle anticlinal clusters, whose genetic mechanisms and the key factor on hydrocarbon enrichment remain as the exploration targets. Focusing on the largest and most complex anticline within the belt—the N27 Structure, and utilizing the 3D seismic data, we systematically analyzed variations in stratified and segmented structural deformation, and proposed a dual-basement, left-stepping, dextral transpression strike-slip model, from which its structural evolution was comprehensively interpreted in combination with physical modeling experiments validating the model reliability. In addition, s the N27 hydrocarbon accumulation model was established via geochemical analysis. Results reveal that the N27 Structure exhibits significant intra-structural heterogeneity, and its planar configuration can be segmented into three distinct domains: northern segment, central segment, and southern segment. Its evolutionary history comprises four major tectonic phases: syn-rift extension, fault-depression transition, depression-transpression inversion, and post-rift thermal subsidence. The structural deformation was jointly controlled by basement-involved faults and regional stress fields. During the Longjing Movement (5 Ma), the older NE-striking en echelon fault systems underwent dextral transpressive strike-slip deformation, culminating in compressional amalgamation via fault reorganization. Moreover, physical simulation experiments were designed based on the kinematic model yielded robust results, demonstrating high geometric consistency with actual structural features in terms of local structural configuration and critical fracture development patterns, thereby validating the reliability of the proposed model. At last, our integrated analysis of hydrocarbon charging episodes from drilling data revealed that the primary control on localized hydrocarbon enrichment in the N27 Structure was the efficiency in the migration of major fault systems. The southern segment exhibits weaker late-stage fault activity and a larger angle between fault planes and the maximum principal stress direction, resulting in significantly lower hydrocarbon migration ability compared to the central and northern segments. Overall, a multi-episodic, fault-controlled differential accumulation model was established for the N27 Structure, in which the central-northern segment was identified as a favorable hydrocarbon enrichment zone. This understanding provides critical guidance for the exploration strategies in the central anticlinal belt.