Abstract: Based on spatial autocorrelation （SPAC） method, the dispersion curves of Rayleigh wave have been extracted from the microtremor recorded by 21 stations belong to the dense short-period array deployed in Guangdong-Hong Kong-Macao Greater Bay area, and then the inversion for shallow S-wave velocity structures within a depth of 1 km beneath the Panyu district, Guangzhou city, have been performed. The results show that the velocity beneath the array is obviously low within 0.25 km depth, ranging from 1.17 km/s to 1.59 km/s, while the velocity increases steadily to 2.88 km/s between 0.25 km to 1 km depth. This indicates that the stability and the reliability of the method, which also implies that the SPAC is an effective, economical and environmental method for detecting the shallow fine structures in densely populated urban areas, and it will play an increasingly important role in the exploration of shallow structure in urban areas in the future.