In order to unify the determination method of available phosphorus in inorganic fertilizers globally，three existing methods are reviewed and studied.Chinese standard method for arbitration (GB/T 8573)，the method of EU standard (EN 15959)，and the method of traditional international standard (ISO 6598)are compared.The results show that there is no significant difference on the test results among these three methods.The method of GB/T 8573 is recommended by ISO/TC 134 as the basis for the new international standard of ISO/DIS 22018.An international ring comparison test has been conducted according to the ISO/DIS 22018，verifying the wide applicability and high precision of the GB/T 8573 omalytical method，and is a good testing method which can be used world-widely.