The degree of cross-linking of corn starch with epichlorohydrin (ECH) was investigated by determining the quantity of reacted ECH, which meant the starting quantity minus the unreacted one. Generally, on analytical technique of ECH, the following colorimetric determination has been used. The glycerol produced on hydrolysis of ECH by NaOH was oxidized to formaldehyde by sodium metaperiodate, which was detected by the reaction of chromotropic acid, and the quantity of formaldehyde was determined by absorbance at 570 nm by spectrometry. The special heat resistant vessel for ECH hydrolysis was prepared. The most suitable condition of hydrolysis was obtained through trial and error experiments. The degree of hydrolysis of ECH to glycerol was about 86%. Using the total organic carbon analyzer (TOC), the quantity of carbon of ECH in a solution was measured as the quantity of CO2 produced by complete combustion. The analytical results of both methods were well agreed, but it was considered that the spectrometry was complicated, time consuming and the narrower rang of determination compared with TOC method.