Abstract: In this paper, different evaluation method on amount of phosphate application cotton field soil was studied by field experiments and laboratory simulations. The results show that the calculated phosphoric fertilizer application amounts of loamy sand cotton field were P2O5 148,173,168 and 150 kg/ha using the method of fertilizer efficiencies function, phosphate adsorption isotherm, phosphate adsorption coefficient and phosphate fertilizer index, respectively; and the phosphoric fertilizer application amounts on loamy cotton field were P2O5 138,160,153 and 172 kg/ha respectively. Based on our experiments, the method of phosphate adsorption coefficient was recommended because of its easy operation and high precision.