The electronic properties of four metallofullerenol samples (La@C82(OH)32, La@C82(OH)24, La@C82(OH)18, La@C82(OH)12) and La@C82 were investigated by synchrotron radiation photoelectron emission spectra (PES). A new emission peak with binding energy of 13.9 eV, which is attributed to La 5d orbitals coupling with nanocage orbitals, is observed in PES of La@C82 for the first time. This suggestion is also supported by previous DFT calculations. Furthermore, the new emission peak disappears when the surface of La@C82 is modified with specific numbers of OH groups, which means the electron orbital coupling between inner metallic atoms and outer nanocage in metallofullerene could be shielded by surface modifications on the outer nanocage.