A size-exclusion chromatography able to study conformational change during protein denaturation was proposed by comparing the correlations between protein biophysical properties and chromatographic behaviors. The relative volume of denatured protein may be compared by size-exclusion chromatography in term of changes in retention time. The number of forming denatured species can be determined by chromatographic peak number. The expansion extent of protein may be described using changes in peak shape and peak number. The exposure of aromatic amino acid residues in denatured proteins can also be deduced from peak height under different wave lengths. We utilized the established size-exclusion chromatography to examine the denatured aspects for liquid and solid a-amylase upon long term storage under lower temperature, to discuss the influence of denaturation time and denaturation temperature on unfolding behavior of proteins.