Three analytic methods determined available phosphorus contents of soil samples were adopted inthe paper to study correlation of these methods. Results showed that mean value of Olsen-P method assaying phos-phorus contents was 1.36 times of that of Bray-P method, and they were very significant correlated. Both Olsen-Pmethod, Bray-P method and M3 method were well correlated. Correlation between M3 method and classic methodswere analyzed with mathematical statistics method, which was helpful to clarify mutual relation of available phospho-rus contents by three analytic methods and their availability. This provides reference for widespread of M3 methodand fully excavate available phosphorus values determined by Olsen-P method, Bray-P method using M3 method ascriterion.