This book takes a multiscale approach to explore the plastic forming and deformation of metals, spanning a wide spectrum from the macroscale to the mesoscale, microscale, nanoscale, and atomic levels. Using advanced simulation techniques, including macroscopic finite element, crystal plasticity finite element, cellular automata, discrete dislocation dynamics, molecular dynamics, and first-principles methods, the book reveals the fundamental physical nature of metal plastic deformation. It also establishes a complete theoretical framework. Taking a multidisciplinary approach, the study draws on mechanical manufacturing science, materials science, solid mechanics, quantum mechanics, and computational science. As such, it provides an integrated, panoramic view of multiscale simulation by combining classical scientific theories with modern numerical methods. All simulation cases are based on original research and demonstrate cutting-edge numerical technologies and pioneering approaches to understanding the plastic deformation mechanisms of metals by coupling multiscale simulation methods. This work will serve as a valuable reference for researchers, students, and professionals in mechanical manufacturing, materials science, and solid mechanics seeking deeper insights into the plastic deformation mechanisms of metals.