Since lack of precision and reliability in home-made vibration detection equipment reduces the efficiency of maintenance, improving the performance of these vibration test devices is urgent. This paper first analyzes the vibration noise, then describes the signal preprocessing method in terms of the complexity of helicopter vibration noise. Finally, the self-adaptive synchronous full-period- sampling averaging short-term Fourier transform method is discussed. Practical verification shows that this method can provide greater accuracy and precision than other algorithms, as it is more adjustable, less influenced by measured signals, and has better real-time performance. This approach is also appropriate for other rotor vibration tests.