Abstract: To address the limitation of conventional simulation modeling methods in accurately representing the actual geometric morphology of packaged microstructures, this paper proposes a refined modeling and high-fidelity analysis approach based on real geometric configurations. A high-precision computed tomography (CT) system is employed to scan a BGA-packaged printed circuit board (PCB) specimen. The inspection revealed that voids are commonly present inside solder joints, with 120 out of 144 joints (83.3%) containing voids. Statistical analyses are conducted on joint diameter, equivalent diameter, and internal void morphology. By converting the acquired three-dimensional digital image data of the solder joints into tetrahedral mesh models and incorporating the Anand viscoplastic constitutive model in finite element simulations, the proposed method enables a more accurate characterization of the stress and strain mechanical responses induced by irregular surface geometries and internal voids. The simulation results are consistent in magnitude with theoretical stress calculations. Further analysis indicates that under temperature cycling loading, both the surface geometry and internal voids of solder joints significantly affect the stress distribution under tensile and compressive loads, leading to increased equivalent creep and consequently a marked reduction in the fatigue life of the PCB. The proposed method effectively overcomes the inadequacy of traditional modeling approaches in reflecting the actual solder joint structure, enabling a more accurate and refined assessment of the thermal fatigue life of PCBs containing voids, while also offering predictive capability regarding the initiation site and propagation direction of cracks.