The farinfrared reflection spectra of the oxide superconductors MBa2Cu3O7-δ (M = Y, Sm, Gd, Eu) are reported in this paper. The spectra cover the frequency region of 40-360 cm-1, and the temperature varies from 4.2 K to 300 K. All the spectra of this series of oxide superconductors exhibit the same kind of structure: there are five reflection peaks and three inversion structures. The first two peaks at lower frequencies are identified to be associated with the collective vibrations of Ba, Cu, O ions and M, O ions, with B1a symmetry; other three peaks result from the bending vibrations of the Cu-O bonds. The three inversion structures in the spectra may be correlated to the superconducting energy gaps.