Abstract: This paper introduces the structure design about a kind of folded MCU(modular concept unit) uni-versal case of airborne electronic equipment. The case design standard, requirements and detailed solution, analysis of heat, vibration, electromagnetic compatibility and their design ideas are described. This case is an independent LRU(line replaceable unit), has open system structure, its left and right side door can turn around the case shaft. It's shape, size, outward mechanical and electrical connectors agree with the connector requirements about civil airplane eectronic equipment in HB7390 standard. The products and their design ideas have reference value for modern military and civil airborne electronic equipment.