Abstract. airplane oil pressure reservoirs are major fuel supplying parts of airplanes to have flight maneuvers. Since they are always working under alternating loadings, they are prone to produce fatigue fractures. Therefore, they will undergo vibration endurance tests in general. And the fixed-frequency vibration endurance test is commonly used in engineering. This paper has established a finite element model for the vibration test system, taken into consideration the influence of liquid fuel and introduced the fluid-solid coupling method to conduct harmonic response analysis on different excitation conditions with MSC.Nastran, thus obtaining the stress distribution under different loading conditions. Moreover, the results have been compared with the test results to verify correctness of the method, thus providing references for the improvement in structural design.