In view of the sensitive characteristics of cold atom inertial measurement equipment to low-frequency vibration, it is necessary to analyze the environmental vibration characteristics, especially the use requirements of extracting and analyzing the low-frequency environmental vibration characteristics. A new spectrum transformation method which can adjust the resolution of data near each frequency point after frequency domain transformation is summarized. At the same time, this method can not only effectively deal with the problem of spectrum aliasing, but also effectively reduce the impact of unreasonable weighted transformation on analog signal spectrum analysis. The spectrum transformation method is used to analyze the actual measurement data to determine the effectiveness of the method.