For the structural analysis of the polymer having a 3-methylsulfinylpropionyl group (PVAcSOMe) obtained from the precursor sulfide polymer, NMR (H-1 and C-13) behaviors of its model compounds, methyl 3-methylthiopropionate (1), methyl 3-methylsulfinylpropionate (2) and methyl 3-methylsulfonylpropionate (3), were examined. In H-1-NMR spectra of the 3 compounds, the overlaps of the peaks were observed between protons underlined in CH3SO CH2CH2, CH3SCH2 CH2, and CH3SO2CH2CH2, while in their C-13-NMR spectra, the overlap of chemical shifts of all carbons was not observed. From the relation between pulse delay and peak-area ratios the quantitativeness of C-13-NMR was checked. The structural analysis of the sulfoxide polymers was found indirectly by means of H-1-NMR spectroscopy (the mathematical treatment of peak areas) and directly by means of C-13-NMR spectroscopy.