Laser quenching, as one of the key technologies for surface strengthening of medium carbon steel, significantly influences the deformation of the workpiece due to the nonlinear structural characteristics during the processing. However, traditional simulation methods are mostly based on linear assumptions, making it difficult to accurately predict the quenching deformation in the unsteady heat transfer process of laser quenching, resulting in a significant deviation between simulation and experimental results. To address this, this paper proposes a simulation and analysis method for the deformation of medium carbon steel laser quenching based on nonlinear structural characteristics, considering the nonlinear high-temperature mechanical properties of medium carbon steel, the nonlinear deformation, and the nonlinear boundary constraints. The necessity of considering the nonlinear structural characteristics of medium carbon steel in laser quenching simulation is also discussed based on the simulation analysis.