In order to improve the physic-chemical properties of Konjac glucomannan and extend its application field,konjac glucomannan was modified with hydrophilic carboxymethyl group and hydrophobic stearate group by microwave.The effects of the amounts of the methyl stearate,sodium hydroxide,microwave reaction time,and the temperature on the degree of substitution(DS) were studied by single factor experiments.Based on these studies,the optimum reaction parameters of preparing SCMK were obtained by revolving orthogonal combinatorial design experiment,and its physical-chemical properties were investigated.The results showed that the amount of the methyl stearate,the amount of the sodium hydroxide,reaction temperature and time were about 14.0%~14.4%,5.85%~6.36%,85.9~87.5℃ and 10.1~10.4min,respectively.The percentage of SCMK with DS value of 0.020 was more than 95%.Compared with the carboxymethyl konjac glucomannan,the viscosity of the SCMK increased,the ability of anti-alkaline and emulsifying capacity and its stability improved.SCMK is a better emulsifier.