Natural clinoptilolite were modified by five different valence state cationic salts. The differences of adsorption ability to ammonia nitrogen were studied with particle morphology, channel characteristic, cation exchange capacity and adsorption ability to ammonia nitrogen taken as evaluation indexes. EDS test revealed that the metal cation content corresponding to five kinds of modified salts in the clinoptilolite will increase with K+ increasing most in KCl modified clinoptilolite. The results of specific surface area and pore size distribution test indicated that the specific surface area of KCl modified clinoptilolite decreased least, whereas AlCl3 modified zeolite dropped most. The mesoporous volume of NaCl and KCl modified clinoptilolite increased most, but macroporous volume reduced most.However the clinoptilolite modified by MgCl2 and CaCl2 showed little change. Cation-exchange capacity order of the modified zeolite was NaCl＞AlCl3＞CaCl2＞MgCl2＞KCl. The ability of clinoptilolite for removing ammonia nitrogen was found to be positive correlation with cation-exchange capacity, but there was a big difference in the cation-exchange capacity of salt modified zeolite with the same valence. The results indicated that the cation valence was not positive correlation with cation-exchange capacity and ammonia nitrogen removing ability.