Studies have shown that physical parameters such as size have obvious influence and relevance on the sound spectrum structure. In order to study the new detection technology of sound recognition of compaction of soil, this article conducted a large number of indoor soil sample hammering tests. The timbre features of the sound are extracted by the impact sound feature extraction method based on the principle of auditory perception, and the focus is on the correlation between frequency domain eigenvalues such as spectral centroid and different compaction of soil. By grouping and analyzing the multiple sets of acoustic samples after the different compaction of soil samples are excited, we found that the centroid feature of the subband spectrum can well represent the compaction of soil, and the two have a strong correlation; the maximum correlation coefficient is up to 0.81. The research results show that when the reasonable hammering force range of exciting soil is 30 N~89 N, the subband spectrum centroid feature is used as an index to characterize the compaction of soil, which can be used to infer the compaction of soil.