<p>The Sn58Bi solder alloy is widely used in microelectronics as a low-temperature soldering alloy, with creep being its notable deformation mode. To effectively characterize the creep behavior of this alloy, a uniaxial-tensile-creep test was designed herein. The creep deformation mechanism was analyzed by comparing the microstructure of the alloy before and after the test. The relevant creep material constants were obtained by fitting the experimental data with the Norton power-law and Kachanov–Rabotnov (K–R) creep models, which were then used to theoretically predict creep strain. In addition, the two models were implemented in finite-element simulations through custom material constitutive equations. Results suggest that only the second and third creep stages are notable. During creep, the numbers of subgrain boundaries and low-angle grain boundaries as well as the nucleation rate of recrystallized grains considerably increase, inducing grain refinement. The predictions of the K–R model are more consistent with the creep test results than those of the Norton model, and the minimum fitting accuracy of the K–R model is 0.865. The K–R model is considerably more suitable here while Norton model could not describe the third creep stage. The simulated and theoretical results are consistent, indicating that the employed simulation method effectively describes the creep characteristics of the Sn58Bi solder alloy. Overall, the proposed method and constitutive model parameters are effective for analyzing the creep and reliability of Sn-based alloys employed in microelectronics.</p>