Abstract: Soil matrix thickness is an important index in the investigation of ground substrate. The topography and geomorphology of Arong Banner are mainly low mountains and hills. The cost of using traditional drilling methods to investigate the soil matrix thickness is high, and the construction is difficult. While the microtremor horizon-to-vertical (H/V) spectral ratio method has strong anti-interference ability and flexible construction, which is convenient to complete areal investigation work. In this paper, the spectral ratio method was used to investigate the 1 km×1 km network. Combined with the spectral ratio curve and borehole data, the authors summarized the depth-frequency empirical relationship of the study area, and calculated the soil matrix thickness distribution in the area. The results show that thickness of the soil matrix in the area is estimated to be between 9~60 m. And it generally shows a trend of gradually deepening from northwest to southeast, influenced by ancient river channels. The boundaries and extension directions of the ancient river channels can be delineated based on the undulating interfaces of bedrock. The study could provide references for determining the thickness distribution of soil matrix in low hilly areas.