In order to clarify the differences in soil phosphorus forms and phosphatase activities in different forest types, we investigated the characteristics of soil properties, phosphorus (P) fractions, and phosphatase activities in a secondary forest and four artificial plantations (Camellia oleifera, Amygdalus persica, Myrica rubra and Cunninghamia lanceolata) in Lutou National Station for Scientific Observation and Research of Forest Ecosystems, Hunan Province. Correlations among soil properties, phosphorus fractions and phosphatase activities were analyzed, and the influencing factors driving the differences in soil phosphorus forms and phosphatase activities were identified. The results showed that:(1) the contents of soil organic carbon (SOC), total nitrogen (TN), ammonium nitrogen (NH₄⁺-N) and the activities of phosphatase in the secondary forest were higher than in the four plantations. (2) the content of residual-P was the highest in the five forest types, and residual-P was the dominant phosphorus form in forest soils. After forest conversion, resin extractable inorganic P (Resin-Pi) increased significantly in Amygdalus persica and Cunninghamia lanceolata plantations. The contents of NaHCO₃ extractable P (NaHCO₃-Pi, NaHCO₃-Po) increased significantly in Amygdalus persica and Camellia oleifera plantations, whereas the content of NaOH extracted organic P (NaOH-Po) decreased significantly in all plantations. The contents and proportions of easily-available P, moderately-available P and non-available P in soils differed significantly among the five forest types. The proportion of easily-available P in total P was higher in Amygdalus persica and Camellia oleifera plantations than in other forests, while a higher proportion of moderately-available P in total P was found in Myrica rubra plantations and Cunninghamia lanceolata plantations. The proportion of non-available P in total P was higher in Camellia oleifera and the secondary forest compared with other forests. (3) correlation analysis demonstrated that easily-available P was positively correlated with total potassium (TK), moderately-available P was positively correlated with nitrate nitrogen (NH₃^--N), non-available P was positively correlated with SOC, TN, NH₄⁺-N, and phosphatase activity was positively correlated with SOC, TN, NH₄⁺-N. In conclusion, the conversion of secondary forest to plantations not only changed the soil total P contents, but also affected the transformation of phosphorus forms, resulted in the differences of the occurrence of P in soil.