Abstract: The dynamic changes of the quantity and the phosphate-solubilizing intensity of phosphate-solubilizing bacteria in the rhizosphere of Leymus chinensis at different developmental stages in Songnen Plain were studied.The study showed that the quantity of phosphate-solubilizing bacteria in the rhizosphere and nonrhizosphere of L.chinensis at different developmental stages showed the change trend of the single peak curve and reached the maximal value at the post-fruiting vegetation stage.Both inorganic phosphobacteria and organic phosphobacteria showed obvious rhizosphere effects.The quantity of organic phosphobacteria was more than that of inorganic phosphobacteria.The phosphate-solubilizing intensity of phosphate-solubilizing bacteria in L.chinensis at different developmental stages all showed the change trend of the single peak curve.Except post-fruiting vegetation stage,the phosphate-solubilizing intensity of inorganic phosphobacteria was higher than organic phosphobacteria.