The Anchang block has a complex geological structure, and research on its rock mechanics and in situ stress characteristics remains insufficient, resulting in serious drilling problems such as lost circulation and wellbore collapse, which pose significant overall safety risks. To achieve cost-effective shale gas development in the Anchang syncline, it is essential to investigate the in situ stress characteristics of the reservoir, establish rock mechanics parameters and an in situ stress calculation model, perform detailed stratigraphic subdivision based on the geological structural characteristics of the Anchang syncline, and analyze the vertical and lateral distribution characteristics of in situ stress parameters and calculation models. The results show that the lower strata of the Shiniulan Formation and Hanjiadian Formation exhibit strong overall elasticity and high rock strength, with the greatest overall failure resistance, followed by the Xintan Formation, and then the Longmaxi Formation and upper Hanjiadian Formation. The elasticity and strength of strata in the core of the Anchang syncline are greatest, followed by the near-core area and steep slope zone of the western wing, and then the gentle slope zone of the western wing. Overall, stratigraphic strength shows an increasing trend from west to east, with greater increments closer to the core. The triaxial in situ stress of the Hanjiadian, Shiniulan, Xintan, and Longmaxi formations exhibits similar variation patterns, with greater increments closer to the core. The triaxial in situ stress is greatest in the syncline core, followed by the near-core area and steep slope zone of the western wing, and is lowest in the gentle slope zone of the western wing. The characterization of rock mechanics and in situ stress in the Anchang syncline is of great significance for improving drilling efficiency, reducing drilling costs, and accelerating regional exploration and development.