In this study, we primarily employed COMSOL, a finite element method analysis software, to investigate the heat dissipation of power transistors, with the TO-220 package design from Onsemi serving as a reference. The focus was on analyzing the structural parameters of the chip carrier and their impact on the thermal management of power transistors’ packaging. By varying the structural parameters of the chip carrier within the packaging area, including its length, thickness, and height, we examined how these changes affect heat dissipation. The results of the analyses indicated that the presence of a chip carrier, as compared with the unsealed model, led to a reduction in the maximum temperature by 15 ℃. The simulation results demonstrate the importance of the chip carrier’s design in enhancing thermal performance. The ultimate goal of this research was to modify the packaging model in such a way that the maximum temperature of the power transistor packaging was maintained below 175 ℃. This temperature threshold is critical for ensuring the reliable operation and longevity of power transistors in high-performance applications. By optimizing the packaging design and improving heat dissipation, in this study, we contributed to the advancement of more efficient and durable power transistor solutions for next-generation electronic devices and systems.