Addition of thermo stable α-amylase during double screw extrusion cooking of rice was carried out and DE value,agglomeration rate,viscosity,colour with and without the addition of enzymes were studied.The results showed that the addition of thermo stable α-amylase could increase the degradation degree of starch.After dissolution,extruded rice powder had a lower agglomeration rate.Optimized parameters were obtained by response methodology as follows: terminal barrel temperature 136.2℃,screw rotating speed 100 r/min and enzyme concentration 36.35 u/g.Compared with the control samples,the rice powder obtained after optimization showed better solubility,DE value increased from 1.06 to 13.58,agglomeration rate decreased from 32.0% to 11.25%,the viscosity decreased from 113.9 mPa·s to 88.6 mPa·s,and the almost same color.