With the rapid development of wireless communication technology, multi-purpose radio microsystems are increasingly used in military, aerospace, and civilian applications. However, the higher integration density of these systems has led to significant thermal management challenges, directly affecting their reliability and performance. This paper focuses on the thermal management design and implementation techniques of Multi-Purpose Radio Microsystems. Through thermal simulation analysis and experimental verification, the thermal characteristics of a three-dimensional stacked structure are investigated. First, a three-dimensional thermal simulation model of the SiP is established to analyze temperature distribution and thermal resistance under natural and forced convection conditions. Second, an replacement verification scheme based on thermal test chips is proposed, enabling high-precision dynamic thermal monitoring. Finally, the effectiveness of the thermal management technology is validated through packaging process optimization and heat dissipation structure design. The study show that forced convection significantly reduces the junction temperature, with the junction-to-case thermal resistance (Rjc) and junction-to-board thermal resistance (Rjb) measured at 19.103°C/W and 6.03°C/W, respectively.The proposed methods provide valuable insights for future thermal management solutions in advanced electronic packaging.