Corn gluten were steeped with different chemical reagents, 2%urea, 5%tween80, 5% NaCl, 2%L - cysteine, using distilled water as control. Intermolecular forces in corn gluten under different reagents were analyzed using the amount of free starch measuring by iodine calorimetry. By the light microscope, intermolecular structure transformation in corn gluten was analyzed before the treatment and after. The results show that Urea, twain, NaCl, and L-cysteine all can make the starch that closely combined with protein migrate away, in which the effect of L-cysteine and NaCl were better, releasing more free starch. It is found through microscopic observation that the starch granule existing in corn gluten is small granule from cutin endosperm, and microscopic observation results consistent with the free starch results. By analysis of the amount of free starch and the microscopic structure change of corn gluten and the mechanism of measuring intermolecular forces with the chemical reagent, it is demonstrated that disulfide bond and electrostatic attraction were main intermolecular forces in corn gluten, which was the main reason for the search combining with the protein .The effect of intermolecular hydrogen bonds and hydrophobic interaction were weaker.