Using density functional theory,we investigate the vibrational properties and polarization-resolved Raman spectra ofα-PtO2 and obtain the Raman tensor and angle-dependent Raman intensity of α-PtO2.It is found that the polar plot of A1g mode in parallel polarization configuration is useful in identifying the orientation of the crystal.The Raman intensity of the Eg mode is about five times stronger than that of the A1g mode.The Raman intensity is about three times stronger when the wave vector of the incident light is in x or y direction than in z direction.Our work will help the material scientists to characterize the α-PtO2 and to identify its orientation by comparing the experimental spectra with our result.