The Gleeble-3500 thermomechanical simulator was utilized to perform isothermal compression tests on 10B33 boron steel. These tests obtained reliable stress–strain data at various temperatures (including room temperature, 100, and 200 °C), as well as strain rates (0.1, 1, and 5 s−1). This data served as the foundation for establishing constitutive equations based on the modified Johnson–Cook and power-law models, aiming to estimate the flow stress behavior. The evaluation employed the correlation coefficient (R) as a metric to compare the accuracy of predicted deformation behavior against experimental observations. While the flow stress obtained from the modified Johnson–Cook model demonstrated an excellent correlation with the experimental results across the investigated temperature range except for room temperature, it generally exhibited superior tracking of the deformation behavior compared to the power-law model. This study highlights the enhanced capability of the modified Johnson–Cook model in capturing the stress behavior dependence on strain rate and temperature for 10B33 boron steel under various deformation conditions.