During hemispherical resonator gyroscope (HRG) packaging, localized high temperatures cause nonuniform thermal distributions and degrade the stability of key dynamic parameters. To reduce these temperature effects, the HRG thermal field was analyzed using coupled simulations in COMSOL Multiphysics. First, the mechanisms for local high temperatures were analyzed. Second, thermal simulations of getter activation and hermetic welding were performed and optimization strategies were proposed. Third, the effects of housing materials and structural dimensions were investigated to further optimize the temperature effects. Finally, dynamic parameter stability experiments were conducted to evaluate the optimization effectiveness. Compared with the original packaging process, the optimization significantly reduced the disturbance effect of the high temperature on the key dynamic parameters. Throughout packaging, the maximum quality factor (Q factor) reached 1.775 × 10⁷, the frequency split (Δf) remained below 1 mHz and the Q factor inhomogeneity (ΔQ) remained below 3.7%, indicating that the dynamic parameters of the gyroscope were well preserved. Meanwhile, the measured leak rates remained below 1 × 10⁻¹² Pa·m³/s. These results demonstrate the optimization effectively mitigates packaging-induced thermal disturbances, improving dynamic parameter stability with excellent hermeticity. This provides a reliable dynamic parameter basis for the high-performance operation of the HRG.