This paper deals with the relationship among the methods of available phosphorus. determination, phosphorus forms and response of crops to superphosphate on three main soils in Sichuan Province. Results obtained from the experiment showed that Olsen and Al-Abbas methods were suitable for fluvisol and purple soil. Fe-P and Al-P could be extracted proportionally by these methods from soils and both of them were the phosphorus resources in the soils for the crops investigated. Bray Ⅱ method was suitable for yellow soil. Ca-P and Al-P were extracted proportionally by this method, and Ca-P was the phosphorus resource in the soil for the crops investigated.