Abstract: The changes of chemical composition were analyzed during the production of KeDong fermented soybean curds, and the rule of chemical composition changes was revealed.Crude protein and crude fat content of sofu pieces showed a declining trend significantly (p<0.05) . Crude protein, free fatty acid content of the sofu soup showed a increasing trend significantly (p<0.05) . Free amino acid nitrogen, total acid of sofu continued to increase prominently ( p < 0. 05) . Reducing sugar of sofu pieces showed a increasing trend significantly (p<0.05) , reducing sugar of sofu soup had a increasing trend, but the data was not stable. pH of Sofu went down dramatically. Salt content remained stabilization, and water content had significant change (p <0.05) . Certain theoretical guidance was provided for the quality and process improvement of fermented bean curds.