Abstract: The wear resistance and fatigue strength of crankshaft journal surface directly determine the reliability and lifespan of automotive engines. Medium-frequency induction hardening technology has become the mainstream process for surface strengthening of modern crankshafts due to its significant advantages, including rapid heating, minimal deformation, low energy consumption, and efficient automation. This paper systematically analyzes the basic principle of medium frequency induction hardening and combines it with the mass production process to deeply analyze the key indicators of quenching quality, their influencing factors, and control methods. The aim is to provide theoretical basis and practical reference for the optimization and stable production of crankshaft induction hardening process.