The invention discloses a method for testing the low-frequency inherent frequency of an aircraft engine sensor, comprising the following steps: I, designing a vibration workbench and configuring at least two acceleration sensors for an external mass spectrograph; II, preliminarily determining the weak position of a sensor according to the structural mechanical analysis, installing and fixing the sensor to the vibration workbench with a clamp, and adhering the acceleration sensors to the fixed part and the weak position of the sensor in a one-to-one correspondence manner; and III, controlling the vibration workbench to sweep frequency in any direction of a normal plane of a sensor to be tested, recording an experimental result through the mass spectrograph, and determining a frequency point at which the response frequency of the weak position is six times more than the frequency sweeping excitation magnitude as the inherent frequency point. By adopting the test method of the invention, a feasible scheme for detecting the inherent frequency of an aircraft engine sensor is provided, the inherent frequency of such products can be detected rapidly and effectively, a reliable basis is provided for strength design of the products, and the strength level of the sensors can be increased dramatically.