The study was on the preparation technology of cold-water-soluble corn starch by microwave treatment,used corn starch as raw material and ethanol-lye solution as the Extraction solvent. Single factor experiments and orthogonal test L₉(3⁴) were used to the experiment. The results showed that the best optimum conditions of preparation were material liquid ratio（g: ml） 1:1,ethanol concentration is 80%,the lye adding amount 11g/100mL,the microwave processing time 3min,microwave power 400W. The best Solubility of cold-water-soluble corn starch was 59.12%.