<p>Microcracks are prevalent defects in mechanical structures, and their propagation behavior under cyclic loading dominates structural integrity and service life. Conventional numerical methods for three-dimensional fatigue crack growth analysis suffer from high computational complexity and poor convergence, limiting their engineering applicability. To address this challenge, this study proposes a Kriging-based surrogate model for high-efficiency prediction of microcrack propagation behavior, validated by the consistency between experimental fatigue data and finite element analysis (FEA) results. A five-dimensional feature space is constructed to map the nonlinear relationship among fatigue parameters, stress ratio, residual stress, load amplitude, and crack growth rate, enabling direct mathematical characterization of crack evolution. Numerical verification shows that the model achieves a prediction error of less than 5% compared with high-fidelity FEA results, while reducing the time cost of a single fatigue life assessment by three orders of magnitude. Meanwhile, the model circumvents the complex remeshing and convergence control procedures required by traditional FEA methods. This work provides a highly efficient and accurate tool for fatigue life evaluation of engineering structures, which is of great significance for improving the reliability of damage tolerance design.</p>