• Fractal analysis provides a quantitative mathematical framework for describing complex, irregular metal surface and interface geometries that conventional Euclidean methods cannot capture.
• The review systematically covers six categories of metal material surfaces/interfaces (precipitates, grain boundaries, deposited films, fractures, machined surfaces, wear surfaces) and links fractal dimension to material properties.
• The establishment of quantitative structure–property relationships through fractal dimensions enables predictive analysis of metal material processing and performance across nano-to-micro scales.
• Future work should focus on revealing the deep influence mechanism between fractal dimensions and properties, and expanding research scope, imaging techniques, and fractal calculation methods.