In this study， porous corn starch (PS) was prepared by compound modification of corn starch with α-amylase and glucoamylase， and the PS was modified by octenyl succinic anhydride(OSA). The optimum preparation conditions were investigated with oil absorption ratio and degree of substitution(DS)， and the absorbability and sustained-release properties of OSA-PS as curcumin microcapsule wall material were discussed. The results showed that the optimum preparation conditions of PS were as follows: enzyme dosage 3%， enzyme ratio 1∶5(g/g)， reaction time 10 h， reaction temperature 50 ℃， pH 6.0， under which the oil absorption ratio of PS was 139.37%. The optimum synthesis conditions of OSA-PS were as follows: substrate mass fraction 25%， pH 8.5， anhydride 3.5%， reaction time 4 h， reaction temperature 40 ℃. Under these conditions， the substitution degree of OSA-PS was 0.02026， and the oil absorption ratio was 120.05%. SEM results showed that the modified starch formed obvious pore structure. The carbonyl structure in the FT-IR results indicated that the esterification reaction was successfully carried out. The results of XRD spectrum showed that the modification process occurs in the amorphous region. The OAS-PS/CS-Cur microcapsule has good encapsulation efficiency and sustained-release properties.