In light of the environmental pollution resulting from the excessive use of chemical fertilizers, several methods, including the analysis of morphological and cultural characteristics as well as ITS rDNA sequencing, were utilized to identify the strain and evaluate its phosphate solubilizing capacity. A controlled greenhouse pot experiment was then conducted to assess the effects of the phosphate solubilizing bacteria strain Y-5 on crop growth and soil fertility. The identification results revealed that the phosphate solubilizing strain, Y-5, belongs to Pseudomonas donghuensis. Under liquid culture for 5 days, the ratio of the phosphate solubilizing ring's diameter to the colony's diameter (D/d) was 3.51. Notably, strain Y-5 exhibited exceptional phosphate solubilization efficiency, with a maximum phosphate solubilizing amount of calcium phosphate reaching 432.25 mg/L. Furthermore, the highest phosphate soluble content of lecithin was 116.37 mg/L, highlighting its robust phosphate solubilizing capacity. The pot experiment results revealed that the modified biochar of strain Y-5 effectively enhances the content of available phosphate and organic matter in soil. Additionally, the modified biochar of the Y-5 strain exerted a significant growth-promoting effect on corn seedlings. Based on the indices of maize seedling growth and soil property changes, it was determined that the optimal application ratio of Pseudomonas donghuensis modified biochar was approximately 10 g/kg. This research result significantly reduced the cost of popularizing and applying phosphate solubilizing bacteria modified biochar and served as a new agricultural material with good prospects for popularization and application, potentially contributing to the green and sustainable development of agriculture in the future.