A method and a system for acquiring the natural frequency of a diaphragm, wherein, the method comprises: selecting test frequency points in a closed space, converting an electric signal into an acoustic signal, directing sound into the closed space, and acquiring the acoustic pressure of each test frequency point; adjusting the electric signal until the acoustic pressure of each test frequency point is the same; converting the adjusted electric signal into an acoustic signal; acquiring the displacement generated by the vibration of the diaphragm; and taking the frequency corresponding to the maximum displacement of the diaphragm as the natural frequency of the diaphragm. By adopting the method and system, the natural frequency of the diaphragm is determined by acquiring the maximum displacement of the diaphragm. Moreover, the process of acquiring the natural frequency of the diaphragm is not affected by surrounding environment, and therefore the acquired result is more accurate.