The study of non-exchangeable potassium release rate is extremely important for the management and proper use of soil resources as well as for the availability and potency of potassium supply, especially in soils containing potassium. The perpuse of this research was investigation of the fixation of non-exchangeable potassium by different extractants after continous extractants in a short time in vermiculite mineral. The experiment was arranged in a completely randomized design having three replicates. Treatments included vermiculite mineral and four extractants (hydrochloric acid, calcium chloride, citric acid and oxalic acid). Non-exchangeable potassium extraction was performed by different extractants with a concentration of 0.01 M in ten consecutive half-hour times. The results of analysis of variance showed that the effect of extractant on the amount of potassium release was significant (p<0.01). Cumulative K release maximum for vermiculite treatment for hydrochloric acid, calcium chloride, citric acid, oxalic acid solutions and control sample was estimated 160.7, 62.1, 140.1, 95.2 and 121.2 mg/kg, respectively. The highest release amount related to Hydrochloric acid extractant and calcium chloride extractant had the lowest release amount. Potassium release data were fitted with different kinetic equations (including Elovich, parabolic diffusion, power function, order one and zero order) for investigation of the non-exchangeable potassium release kinetics, and the power function, parabolic diffusion and Elovich equations suggested as the best equations to predict the non-exchangeable potassium release from the vermiculite mineral. Cumulative calcium release Maximum for vermiculite treatment by extractants of hydrochloric acid, calcium chloride, citric acid, oxalic acid and control sample were estimated 1600, 29920, 3040, 1120 and 3440 mg/kg and cumulative magnesium release Maximum equal to 192, 1872, 1776, 528 and 1392 mg/kg, respectively. Calcium chloride extr