Abstract: In order to solve the high flow density heat dissipation problem of a shipborne portable miniature high-performance signal processing device, a reinforced sealed cabinet is developed by adopting highly efficient heat conduction based on the heat pipe combined with forced air cooling and by the whole machine structure design, module cold plate design, uniform temperature partition design and calculation of the fan type selection. The thermal simulation based on the model established by Flotherm simulation software and the full load test under +50 ℃ are carried out. The result fully verifies that the cabinet design can meet the heat dissipation requirements of portable miniature high-performance signal processing device and the heat dissipation requirements of single module with 100 W power and chip package level heat flow density of 30 W/cm ², which provides reference for design of the same kind of reinforced sealed cabinet.