【Objective】 Phosphorus (P) is an important nutrient for plants. Enough supply of bioavailable P is essential for maintaining the stability of montane ecosystems. Many previous studies have focused on distribution and main driving factors of soil bioavailable P. However, there still are disputes about the synergistic effects of soil parent material, soil age, climate, biological activity, and soil properties on the bioavailable P distribution. The large altitudinal difference of high mountains provides an opportunity for determining the dominant factors and their interactions on the bioavailable P distribution in natural ecosystems. Therefore, the objectives of this study were to investigate the distribution of bioavailable P in profiles along the altitudinal gradient and to clarify the factors impacting the spatial and temporal distribution of bioavailable P in subalpine soils. 【Method】 Four altitudes (2 628 m, 2 781 m, 3 044 m and 3 210 m a.s.l.) were selected for sampling in May 2016. Six soil profiles were randomly set up for each site with a distance larger than 10 m between them. Soil profiles were divided into the four horizons O, A, B and C. One- to two-kilogram soil samples were collected hierarchically from the C to the O horizon. After soil samples were collected, mixed-bed ion-exchange resins bags were inserted into the four horizons (profiles 1~4) at each site. Soil samples were assayed to estimate the content of bioavailable P (Bio-PL). Bio-PL was defined as the inorganic P extracted using 0.5 mol•L^-1 NaHCO₃ (pH = 8.5) followed by colorimetric analysis with a UV2450 (Shimadzu, Japan). Resin bags were recovered to analyze the soil supply of bioavailable P (Bio-PS). Bio-PS was estimated by PO₄^3--P concentrations using an Autoanalyzer 3 (Seal Analytical, Germany). 【Result】 The concentrations and stocks of Bio-PL as well as Bio-PS increased with altitude. The leaching process was more intensified in lower altitudes. This altitudinal pattern of bioavailable P was likely related to a lager loss of bioavailable P in lower altitudes (especially at the 2 781 m site) as shown by increasing soil moisture downward. The concentrations and stocks of Bio-PL decreased with soil depth. The stock of Bio-PL in the O horizon accounted for the largest proportion of the total Bio-PL stock, with an average of 75%. The Bio-PS in the O horizon was larger than 0 mg•kg-1•d-1 in the whole year. Thus, most soil bioavailable P was stored in the O horizon. The higher organic P content and phosphatase activity in the O horizon were the most important factors for this vertical distribution of bioavailable P in soil profiles. Bio-PS in the O horizon at the 2 781 m site was higher in September. For both of the 3 044 m and 3 210 m site, Bio-PS in the O horizon were higher in June and September. Bio-PS in the mineral horizons at the four sites was smaller than 0 mg•kg^-1•d^-1 in most months. The minimum Bio-PS for both A and B horizon were in August at the 2 781 m site, which were -1.143 and -0.943 mg•kg^-1•d^-1, respectively. Biological assimilation and loss with runoff were the main factors controlling the seasonal changes of soil bioavailable P. 【Conclusion】 Bioavailable P in the subalpine soil on the eastern slope of Gongga Mountain showed obvious spatial and temporal variations. The content of bioavailable P increased with altitude, and this altitudinal pattern was likely caused by a larger amount of loss in lower altitudes. Soil P bioavailability was highest in September for the O horizon and lowest in August for the mineral horizons. The seasonal change of soil bioavailable P was mainly controlled by the biological assimilation and loss with runoff.