In order to investigate the influence of irrigation pattern on paddy soil adsorption to ammonia ,the paper collected the paddy soil in Taihu Lake basin under different irrigation patterns to carry out adsorption experiment in laboratory. Results showed that the adsorption dynamic processes on two kinds of paddy soil could be divided into fast stage and slow stage. The result fitted by pseudo-second-order rate equation is the optimum;the theoretic equilibrium adsorptive capacity and experiment equilibrium adsorptive capacity of paddy soil to ammonia nitrogen under controlling irrigation pattern are 454.5 mg/kg and 446.2 mg/kg, respectively,which is higher than that under flooding irrigation pattern.The result of isothermal adsorption data fitted by Freundlich equation is the best. Under the mode of controlling irrigation,the unhomogeneity, reaction strength of absorbing ammonia nitrogen and adsorption capacity of paddy soil all raised.