In this paper, magnetic zeolite was synthesized by kaolinite by using the hydrothermal method. Before crystallization the synthesized Fe₃O₄ magnetic fluid was added so as to synthesize the magnetic zeolite 4A in which Fe₃O₄ content came to 4.48%. Then the zeolite was applied in the adsorption experiments for the ammonia nitrogen in the solution. A combination of XRD and magnetic susceptibility analysis was performed in this synthesized magnetic zeolite 4A. Besides, the experimental data were utilized to fit the adsorption isotherm equation and then to perform the kinetic analysis. The results showed that the loading of Fe₃O₄ had little effect on the crystal structure, and magnetic susceptibility of magnetic zeolite 4A was stable enough to be reused. Two isotherm adsorption models were used and the Freundlich isotherm was in better agreement with the adsorption results. Furthermore, the fitting results of Lagergren quasi second-order rate equation showed that the adsorption rate was controlled by the chemical adsorption, and the adsorption of ammonia nitrogen conformed to the quasi second-order dynamics mechanism.