Abstract: The optimal technical conditions for sulfated modification of konjac glucomannan gel beads were investigated by the quadratic regression rotatable orthogonal design. The results showed that the reaction temperature was the most significant factor to affect the sulfate group content of the final product, the amount of chlorosulfonic acid was the less one, and the reaction time was the least one. The interaction between reaction temperature and chlorosulfonic acid amount was significantly noticeable. The regression equation was at the very significant level without any lack of fit factor. By predication and verification, the optimal technical conditions for sulfate modification were determined as follows: for 10 g konjac glucomannan gel beads, the optimal amount of chlorosulfonic acid was 5.27 mL, the optimal reaction temperature and time were 39.4℃ and 3.88 h, respectively, the sulfate group content of the final products could reach (24.40±1.28)% under the optimal conditions.