Kaolinite as a raw material was modified to prepare a Na-zeolite product via calcination and alkaline treatment. According to the measurement of the cation-exchange capacity, the prepared Na-zeolite product with an ammonium ion-exchange capacity of >75 mg/g can be used to remove ammonia nitrogen in water. The Na-zeolite products were characterized by scanning electron microscopy, infrared spectroscopy and X-ray diffraction, respectively. The refinement of the structure was simulated by a software named Full Prof. The results show that the Si–O stretching vibrations of the prepared product in the range of 1008–1115 cm–1 disappear, only a small bend appears at 1103 cm–1 and the Al–OH vibration peaks at 912 cm–1 and 940 cm–1 both disappear. It is indicated that after calcination and alkaline treatment, the Si–O tetrahedral and Al–O octahedral structures are severely damaged, resulting in changes in the flexural vibrations of Si–O and Al–OH. Kaolinite is a lamellar structure with the space group of C1, classified into a triclinic system, and cell parameters(such as a=0.5154 nm, b=0.8941 nm, and c=0.74 nm). Kaolinite with a lamellar structure is completely dissolved after calcination and alkaline treatment, resulting in the formation of Na-zeolite with a cage cubic structure. Kaolinite as a raw material was modified to prepare a Na-zeolite product via calcination and alkaline treatment. According to the measurement of the cation-exchange capacity, the prepared Na-zeolite product with an ammonium ion-exchange capacity of> 75 mg / g The refinement of the structure was simulated by a software named Full Prof. The results show that that can be used to remove ammonia nitrogen in water. The Na-zeolite products were characterized by scanning electron microscopy, infrared spectroscopy and X-ray diffraction, respectively. the Si-O stretching vibrations of the prepared product in the range of 1008-1115 cm-1 disappear, only a small bend appears at 1103 cm-1 and the Al-OH vibration peaks at 912 cm-1 and 940 cm-1 both disappear. It is indicated that after calcination and alkaline treatment, the Si-O tetrahedral and Al-O octahedral structures are severely damaged, resulting in changes in the flexural vibrations of Si-O and Al-OH. Kaolinite is a lamellar st ructure with the space group of C1, classified into a triclinic system, and cell parameters (such as a = 0.5154 nm, b = 0.8941 nm, and c = 0.74 nm). Kaolinite with a lamellar structure is completely dissolved after calcination and alkaline treatment , resulting in the formation of Na-zeolite with a cage cubic structure.