A new type of anion exchange resin was prepared from cassava stalk (CS) after reaction with epichlorohydrin and dimethylamine in the presence of pyridine and N,N-dimethylformamide. In order to obtain the optimal conditions for the preparation of cassava stalk anion exchanger (CS-AE), the single influential factor experiments were carried out, with nitrate removal efficiency as indicator. Factors like dosage of CS and catalyst, experimental temperatures were examined. The results indicated that the optimal synthesis reaction parameters of dosages were CS: pyridine: dimethylamine = 2 g: 30 ml: 35 ml. The optimal experimental temperature was 100 °C; the catalytic temperature was a key factor in the preparation of CS-AE.