Acidity and alkalinity is a basic property of soil, which is influenced by biology, climate, landform, parent material and artificial activity. This paper selected the soils developed from different parent material and landform positions and land use types in a hill section. The data of pH value of topsoil and bottom soil were got by digging soil profile and experimental analysis. Spatial similarity was analyzed between soil pH and parent material, landform, land use pattern respectively by information entropy theory. The results showed that topsoil pH was mainly influenced by land use pattern, pH value of cultivate soil was lower than natural soil. And the bottom soil pH was mostly influenced by parent material, pH-value of soil developed from sandstone rotten material was the lowest, then the Xiashu loess, the maximal one was sandstones and fuchsia shale material. This paper was characterized by a quantitative spatial relativity analysis between the qualitative and quantitative variables based on unite entropy theory, it could overcome the deficiency existed in the previous studies.