The present paper deals with the characreristics of isothermal phosphate adsorption and desorption of warped irrigated soil collected from Yinchuan Plain in Ningxia. The data of isochermal phosphate adsorption of the twelve soil samples tested in a wide range of phosphorus concentration (up to 3097 ug P/g) were all found to be in close agreement with the Freundlich, Langmuir and Temkin equations. Their correlation coefficients (r) ranged from 0.931 to 0.999, with a very significant level (P<0.01). Among these equations the Langmuir adsorption isotherm seems to be the best fitting model.The P adsorption maxima of the soil samples tested as estimated by the Langmuir equation varied from 172 to 460 ug P/g. Their average was approximately 347±28 ug P/g. The relationships between the P adsorption maxima and some soil properties have been examined by simple linear regression analyses. Results have showed that P adsorption maxima were in fairly significant direct correlations (P<0.01) to the contents of physical clay and CaCO₃ in warped irrigated soil. According to the experimental data in the paper, the isothermal phosphate adsorption curves of soils could be used for predicting the requirement of phosphorus fertilizer for soils.