Abstract: Soil aggregates play important roles in regulating the storage and turnover of phosphorus in soil. This study was conducted to evaluate the regulatory effect of biochar mediated soil aggregates on the form, transformation, and distribution of soil phosphorus. This study was based on long-term field experiments of biochar, four treatments were selected: no fertilization (CK), biochar application (BC), NPK fertilizer application (NPK), and NPK fertilizer combined with biochar application (NPK+BC). After maize harvest in 2021, 0-20cm soil samples were taken to study the effects of biochar on the composition and stability of soil aggregates, as well as the content of various phosphorus fractions in each particle size aggregate. The distribution of phosphorus fractions in soil aggregates and the relative contribution rate of different particle size soil aggregates to different forms of phosphorus were also clarified. The results showed that 1) the application of biochar significantly increased the proportion of coarse aggregates (>2 mm) by 8.7% (CK treatment) and 15.8% (NPK treatment), respectively. The proportion of silt and clay particles (<0.053 mm) was reduced by 11.5% (CK treatment) and 21.8% (NPK treatment), respectively. The application of biochar significantly increased the MWD and GMD of soil aggregates by 9.6% and 22.2%, respectively. 2) The application of biochar increased the content of TPi (total inorganic phosphorus) (mainly manifested in the increase of NaHCO₃-Pi and NaOH-Pi content) in aggregates with particle size >0.25 mm, and also increased the content of TPo (total organic phosphorus) (mainly manifested in the increase of NaOH-Po and Residual-P content) in fine and large aggregates (0.25-2 mm). 3) The application of biochar reduced the relative contribution of silt and clay particles (<0.053 mm) to total phosphorus anddifferent phosphorus fractions, and increased the relative contribution of coarse aggregates (>2 mm) to total phosphorus and different phosphorus fractions, In conclusion, the application of biochar improved the stability of soil aggregates, improved the structure of soil aggregates, and promoted the distribution of phosphorus fractions in soil aggregates with larger particle sizes. The application of biochar is an important agricultural measure to improve soil structure, promote soil phosphorus retention, and reduce the risk of soil phosphorus loss.