Abstract: The property is proved in theory that the distributing ratio of flow in a cooling system for the electronic devices in the electronic equipment cabin is independent of the total flow and the flight altitute of the airplane.The test results are also presented.Therefore, the complex tests of simulating different altitudes of flight can be greatly simplified So, the manpower , expenditure and energy can be saved and the duration of the test can be shortened greatly

Key words: elet ronic equipment, cooling systems, flow dist ribution