Based on the initial P-wave signal data from 472 earthquakes occurring in the Inner Mongolia-Hebei-Liaoning border region between January 1, 2008, and December 31,2021,a fine-grained stress field with a resolution of 0.25°×0.25° was constructed using the comprehensive focal mechanism method. This stress field effectively covers the entire Inner Mongolia-Hebei-Liaoning border area. The results of the stress field inversion reveal the following: ① The main compressive stress field in the Inner Mongolia-Hebei region trends eastward,driven by a tensile stress system resulting from the intense compression along the northeastern margin of the Qinghai-Tibet Plateau. The dominant focal mechanism solutions are normal faulting and strike-slip faulting,with the P-axis generally oriented northeast to east-northeast, and the T-axis oriented northwest to west-northwest. These findings are consistent with previous studies on active tectonic movements and block tension and rifting in the area. ② In the Inner Mongolia-Liaoning border area,there is greater variability in the P-wave data,and the focal mechanisms are more dispersed. In the Inner Mongolia-Liaoning or Hebei-Liaoning border regions,the seismic source mechanisms are predominantly reverse faults,while in southern Liaoning,normal faulting is more prevalent.