A testing system was improved as for the poor stability and accuracy in the water flow test of one aeroengine high-pressure turbine guide-vane. A closed-loop control system and one equivalent circuit were added to the testing device, the seal changed from partial seal around the air intakes to the overall seal covering the up and down edge of the blade, the fixture had four intakes instead of the original two, and the assembly process of air duct was optimized. The testing system after being improved was tested, and it proves that the testing pressure stability and good sealing are achieved, and the repeated measuring error and the dispersion degree of measuring both meet the design requirements as well as testing efficiency is effectively improved.