A simple method to distinguish the TO and LO modes of Raman spectra in optical active uniaxial crystals was proposed in this paper. Using 90°scattering geometry configuration x(z+△y, xz)y, the angle between polarization direction of scattering light and x axis is denoted by δ. Applying the formula of Raman scattering efficiency of polar phonons in uniaxial crystal given by Loudon, we found that scattering efficiencies of TO and LO modes depend on components of Raman polarizability tensor and angle d. If δmaxTO and δmaxLO represent the angles at which Raman scattering efficiencies for TO and LO modes take maximum value respectively, it turns out that sign of δmaxTO and δmaxLO is just opposite. Therefore, according to sign (δmax), TO and LO modes can be distinguished, and anisotropy of Raman tensors can be extracted from the absolute values of δmax.