Phosphorus is a critical nutrient for plant growth and development，but it often exists in forms in the soil that are not readily accessible to plants.In this study，an alkaline phosphatase(PB)derived from Bacillus subtilis HJB17 and a biopolysaccharide(BPS)composite were combined to form an alkaline phosphatase-biocarrier complex(P-BPS) .The enzymatic properties of P-BPS were evaluated，and its activity in soil was assessed.Enzyme activity analysis revealed that both P-BPS and PB exhibited an optimal reaction temperature of 37℃，with P-BPS demonstrating superior thermal stability compared to PB.At 55℃，the enzyme activity of P-BPS remained largely unaffected，and it still maintained substantial activity at 65℃.Additionally，the effects of P-BPS on the available phosphorus content in soil samples from four regions，as well as on soil samples before and after the growth of tomato plants from three regions，and tomato plant growth indicators in two regions were investigated.The results indicated that:(1)In soil samples from four regions with varying initial levels of available phosphorus，the highest increase in available phosphorus content was observed when P-BPS was added at 0.5%，with maximum increases of 40.1%，49.5%，48.6% and 49.1% in Xinyang Henan，Shandong Qingdao，Guangxi Bama and Guangdong Xinhui，respectively；(2)In tomato experimental fields，soil available phosphorus content also increased，with the highest increments observed at 0.5% addition，showing increases of 27.9%，28.1% and 29.0% in Pinggu，Forestry University，and Qingdao experimental fields，respectively；(3)Regarding tomato plant growth，the addition of 0.5% P-BPS resulted in increases in plant height and main root length of 116% and 56%，respectively，in Pinggu experimental fields，and 82% and 90%，respectively，in Beijing Forestry University experimental fields.In conclusion，the exogenous application of P-BPS effectively enhanced the bioavailability of phosphorus in soil，and its direct use could provide a sustainable source of phosphorus fertility in agricultural soils.