<p>30CrMnSi steel, a high-strength alloy extensively utilized in aerospace, shipbuilding, and defense, is highly valued for its exceptional combination of strength, toughness, and wear resistance. Aiming to characterize its hot deformation behavior, isothermal compression tests were conducted within a temperature range of 850–1150&#xa0;°C and strain rates of 0.01 ~ 10&#xa0;s⁻¹. Based on the experimental data, a strain-compensated Arrhenius constitutive model was developed to describe the thermal deformation behavior of the alloy. Error analysis confirmed the reliability of the model, yielding a correlation coefficient of <i>R</i> = 0.98 and an average absolute relative error of <i>AARE</i> = 4.86%. A dynamic recrystallization kinetic model and an average grain size model were further developed to characterize the microstructural evolution of 30CrMnSi steel during deformation. The results show that dynamic recrystallization becomes significant under high-temperature and low-strain rates, and its volume fraction increases progressively with strain. Analysis of the hot working map identified the optimal processing window as a deformation temperature of 950 ~ 1150&#xa0;°C and a strain rate of 0.01 ~ 0.032&#xa0;s⁻¹. Within this range, dynamic recrystallization is complete, and the alloy exhibits favorable hot workability. The constitutive and microstructural models were incorporated into Deform-3D through its secondary development interface, enabling numerical simulation of the hot compression process. The simulations were used to analyze the distributions of equivalent strain, equivalent strain rate, dynamic recrystallization fraction, and average grain size. Comparison between simulated and experimental results showed strong agreement, confirming the accuracy of both the flow stress model and the microstructure model. These findings provide a sound theoretical basis and practical guidance for industrial hot working applications.</p>