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The SERS spectra of oxidized bilirubin (oxidized by oxygen in alikline solution) and biliverdin were obtained. The similarity of these two SERS spectra demonstrated that the bilirubin was oxidised to biliverdin by oxygen in amibent temperature. The informations of these SERS spectra also show that the orientation of bilirubin and biliverdin on surface of silver colloid were different. In the experimental case, the internal hydrogen of bilirubin was formed with the interplanar angle $98\circ$ of the two pyrromethnone rings. The bilirubin was intercalated into the silver colloid with the lactam ring slit on surface slightly. The biliverlin was flat on the surface of silver colloid with the N atom of pyrrole ring C and O atom of lactam ring D prontonated. On the surface of silver colloid the biliverdin adopt a near planar and cyclic helical conformation. And the ring C and D of biliverdin were most near the surface of silver colloid.