In this study, the alkali method was used to extract starch from early indica and organic solvent was used to extract polyphenol from black rice bran. The polyphenol content was determined by using high performance liquid chromatography (HPLC). The free phenol of black rice bran was added to starch-iodine complex solution to study the effects of free phenol with starch-iodine compounds by scanning the changes of absorption spectra. Furthermore, α-amylase was added to the solution to study the effects of free phenol from black rice bran on the digestion of early indica starch. The results showed that free phenol from black rice bran inhibited the combination of starch and iodine. The inhibition of phenol to starch digestion increased with the increase of phenol concentration. The absorption peak moved to short wavelength with the increase of phenol concentration, which is called blue shift. The reason might be that the combination of phenol and starch changed the nature of the starch, which changed its absorption peak. The free phenol of black rice bran inhibited starch digestion through combination of phenol and starch hydrophobic groups.