The method of path analysis was applied to study the difference among phosphorus fractions to the plant phosphorus availability following the correlativity analysis on the basis of the fraction of inorganic and organic phosphorus. The order of relative imPortance of phosphorus fractions to the plant phosphorus availability as follow: Al—P＞moderate resistant organic P＞Fe—P＞moderate labile organic P＞labile organic P＞H₂O—P＞ high resistant organic P＞O—P＞Ca—P. A new way to evaluate correctly the role of organic P in the Plant phosphorus nutrient was supplied by the method of path analysis in this paper.