Phosphorus (P) is an essential element for plant growth, development and metabolism. Soil is a direct donor of phosphorus for plants. Generally, total phosphorus (TP) is plenty in most soils, but its availability to plants is very low. Aluminum (Al) is the most abundant metal element in the earth's crust. When the soil is getting acidified, Al in the forest soil can be activated into Al³⁺ (exchangeable Al, Ex-Al) or Al (OH)²⁺, Al (OH)₂⁺ (hydroxyl-Al, Hy-Al), which might precipitate HPO₄^2-, H₂PO₄^-, and PO₄^3- into hard-to-dissolve P and reduce the P availability in consequence. How to prevent the decrease of P availability caused by the dissolution of Al from acidic soil, which is one of the urgent problems to be solved in forest land management. Forest type and soil layer might affect the characteristics and relationships between inorganic phosphorus (IP) and labile Al, which remains poorly understood up to now. The present study aimed to determine the influence of forest type and soil layer on the concentration and distribution of IP and labile Al in soil, in addition to the correlation between labile Al and IP. The soil was collected by digging in three soil layers (A, B and C layer) of four forest types of Rubus corchorifolius, Pinus massoniana, Phyllostachys pubescens and Citrus reticulata forest in Jinyun Mountain, Chongqing, China. Concentrations of IP and labile Al fractions were measured using the traditional method. Results showed that concentrations and proportions of IP and labile Al in soil were significantly affected by forest types and that of iron-bound P (Fe-P), Ex-Al and Hy-Al in soil were significantly different in soil layers. Among the four forest types, Rubus corchorifolius promoted the formation of occluded P (O-P). Whereas, Pinus massoniana, Phyllostachys pubescens and Citrus reticulata were in favor of the formation of aluminum-bound P (Al-P), Fe-P and calcium-bound P (Ca-P). Citrus reticulata was favorable for the formation of low-active Al species (humic acid-Al, Al-AH), while Rubus corchorifolius, Pinus massoniana and Phyllostachys pubescens contributed the dissolution of labile Al from low-active into high-active species (Ex-Al or Hy-Al). In soil layers, Ex-Al, Al-P and Fe-P mainly enriched in the surface among the three soil layers. Hy-Al concentrated in the second soil layer. Meanwhile, the correlations were significantly positive between Ex-Al and Al-P and Fe-P or between Hy-Al and Ca-P in the soil of four forest types. The concentration and distribution of IP and labile Al fractions in soil were significantly affected by forest types. The dissolution of labile Al from low-active into high-active species significantly affected the concentrations of Al-P, Fe-P and Ca-P. This study can provide theoretical and practical basis for the management of agriculture and forestry on acid soils in southwest China.