Abstract: With the deepening understanding of the sustainable use of land resources, the ground substrate, as the fundamental material layer that supports and nurtures natural resources, is increasingly highlighting its importance in the evaluation of the suitability of arable land. This study aims to explore the intrinsic connection between the characteristics of the ground substrate and the suitability of arable land, as well as how to enhance the scientific and precision of arable land evaluation through the investigation of the ground substrate. Taking Ningbo City in Zhejiang Province as an example, this paper selects 15 indicators from five aspects: physical properties of the ground substrate, chemical properties of the ground substrate, topography, climate, and location conditions. The Analytic Hierarchy Process (AHP) is used to determine the weight of each factor in the evaluation, and the suitability of arable land in the Ningbo area is calculated by weighted summation. The suitability of arable land in Ningbo City shows a characteristic of being higher in the north and lower in the south, and higher in plains than in mountainous areas. The highly suitable areas are mainly distributed in the central and northern plain areas of Ningbo City, accounting for 28.71% of the total area. The moderately suitable areas are mainly located around the urban area and near the front of the mountains, accounting for 20.50% of the total area. The marginally suitable areas are mainly located in the lower mountainous hilly areas on both sides of the ridges with lower altitudes in the central and southern part of Ningbo City, accounting for 35.76% of the total area. The unsuitable areas are mainly located in the higher altitude areas of the lower mountainous hilly areas in the central and southern part of Ningbo City, accounting for 15.03% of the total area. The type, distribution, profile characteristics, and organic matter content of the ground substrate have a significant impact on the planning of arable land use. In the plain areas, the soil matrix areas have a higher suitability for arable land, while in the lower mountainous hilly areas, the gravel and rock matrix areas have a lower suitability. Finally, this paper discusses the limitations of the application of ground substrate investigation in the evaluation of arable land suitability and puts forward suggestions for future research directions.