Autoclave processing parameters for preparing Mung bean resistant starch(MRS) were investigated.The influence of starch pastes concentration,autoclave time,autoclave temperature,storage time and storage temperature on yield was compared by single factor experiment.The mathematical model describing the relationship between the output of MRS and each factor was developed in order to optimize the autoclave processing parameters by Box-Behnken center combination experimental design.The optimum values of the above process conditions were obtained as: starch slurry 27.13%,autoclaving 40 min and storage at 4.77℃.Under such conditions,the yield of MRS was up to 12.63%,very close to the theoretical prediction value of 12.41% and increased by 8.59% compared with the content of 4.04% in the raw Mung bean starch.