To develop a new humectant of tobacco，the effect of KSAP (konjac superabsorbent polymer) applying in tobacco was tested by contrasting with KGM (konjac glucomannan)，propylene glycol and glycerin.The results indicated that at the condition of 22±1℃ and of 40%±2% RH (relative humidity)，KSAP solution had the least weight reduction of 1.119 g，and the tobacco of KSAP had the highest water content of 10.05%，which means the moisture retention of KSAP added in tobacco is better than the effects of KGM，propylene glycol and glycerin. At the condition of 22±1℃ with 90%±2% RH，the moisture absorption rate of KSAP was less than that of propylene glycol and glycerin，which means excellent humidity resistance. IR (infrared spectrum) analysis indicated that hydrophilic group is rich in KSAP. The SEM image showed that KSAP has network structure.