Abstract: Aim ：To study the effect of Eudragit S-100，a pH-responsive polymer，on protein refolding level， using recombinant human keratinocyte growth factor-2(rhKGF-2) as a model protein. Methods ：The refolding of rhKGF-2 was performed by directly diluting denatured rhKGF-2 into a refolding buffer containing different concentrations of Eudragit.The ability of Eudragit S-100 to enhance protein refolding level was investigated using MTT assay，reverse phase HPLC，fluorescence emission spectroscopy and circular dichroism spectroscopy. Results ：The addition of Eudragit S-100 in the refolding buffer significantly increased the rhKGF-2 refolding yield to 71%，when dilution refolding was conducted at 0.5 mg/mL rhKGF-2.The outcome from the refolding study showed possibility of a special interaction between rhKGF-2 and Eudragit，suggesting that the refolding-enhancing ability of Eudragit S-100 was due to this interaction between Eudragit S-100 and rhKGF-2.Mean while，the result showed that the concentration of urea was also an important factor for the optimization of the refolding in the presence of Eudragit. Conclusion ：Eudragit S-100 can significantly increase the refolding level of rhKGF-2.