Qin Shihuang's Terracotta Warriors is one of the major discoveries in the archaeological history of the world. It has become a key issue to identify the composition of polychrome binder of Qin's terracotta warriors in understanding their traditional painting technology and deterioration mechanism to provide conservation strategies. Previous instrumental analysis proposed that the binder in Qin's polychrome samples might be egg. In this work, specific fluorescence, generated by the ovalbumin antibody-egg white interaction was observed on Qin's samples under immunofluorescence microscopy (IFM). Our results demonstrate how specific and sensitive the IFM method is to analyze the organic substances in precious artworks.