Abstract: By using KCl as potassium source，the dynamic adsorption and desorption property of Zhongxiang rectorite in Hubei Province to Potassium ion was studied.The results indicated that the adsorption of K⁺ on rectorite was fast，and the process of the dynamic adsorption matched the ExpAssoc model with the equilibrium adsorption time for 30 min.And the adsorption fit Langmuir isotherm adsorption model with the adsorption quantity of 14.588 mg/g as well.The desorption quantity of K⁺ by HCl solution in pH 5 was minimum and the desorption quantity by Ca²⁺+Mg²⁺ increased with the increasing of (Ca²⁺+Mg²⁺) concentration.The desorption fits Elovich equation and exponential equation(Double constant equation) well.Because rectorite is a good potassic fertilizer sustained-release carrier，so the lower concentration of (Ca²⁺+ Mg²⁺) in the soil is，the better effect of sustained-release is.

Key words: Rectorite, Potassium ion, Adsorption, Desorption