Quercus serrata occurs across a wide soil phosphorus (P) gradient. Plants secrete phosphatase from fine roots and phosphatase degrades soil organic P to release orthophosphate, the only form resorbed by plants. P acquisition traits of Quercus serrata may be adapted to a wide soil P gradient and there may be intraspecific variations in fine-root phosphatase activities. Four fine-root phosphatase activities of Quercus serrata (PME: phosphomonoesterase; PDE: phosphodiesterase; PyP: pyrophosphatase; and PhT: phytase) were measured in 14 forests with different soil P availability. The PME, PyP, and PhT activities differed among the 14 forests. There were intraspecific variations in fine-root phosphatase activities, suggesting that Quercus serrata may have local adaptation in phosphatase secretion. The PME demonstrated the highest activities of the four and had a negative relation with the concentration of soil labile orthophosphate which corresponds to the product of PME reactions. Quercus serrata may secret PME as the primary enzyme and enhances the PME activity in low-P soils. The PDE also had a negative relation with the concentration of monoester P which corresponds to the products of the PDE reaction. We suggest that Quercus serrata can distribute across a wide soil P gradient by regulating four phosphatase activities.