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The shape and shift of Raman peak of solid organics prove to be capable of revealing atomic and molecular level vibration information of aromatic ring structure and its relationship with sample maturation. Raman "D" peaks and "G" peaks of a series of continuously maturated coal samples were measured, and the inter-peak intervals (GD) and peak height ratios (Dh/Gh) were derived and correlated with the vitrinite reflectance (vR o %) of standard coal samples. As a result, two formulae were established by using the two Raman indices for calculation of Raman reflectance (RmcR o %), which is equivalent to vitrinite reflectance. The formula for calculating Raman reflectance indicative of organic maturation using Raman shift inter-peak interval (GD) is RmcR o %= 0.0537 d(GD)-11.21, which is mainly applicable to matured to highly matured carbonized samples of solid organics; The formula for calculating Raman reflectance indicative of organic maturation using Raman peak height ratio (Dh/Gh) is RmcR o %= 1.1659 h (Dh/Gh)+2.7588, which is mainly applicable to carbonized samples of solid organics that are over matured or going to be turned into granulated graphite. Preliminary applications indicate that Raman reflectance "RmcR o %" calculated based on results of Raman spectral analysis of solid organics can be used to characterize sample maturation at molecular level, so enjoying extensive prospects in geological applications. In petroleum geology and coal petrography, vitrinite reflectance (vR o %) is a generally universal index gauging maturation of hydrocarbon source rocks and coals. However, highly matured to over-matured samples would show extensive variations in vitrinite reflectance due to considerable inhomogeneity, which would affect accurate assessment of sample maturation. Recently, peak D and peak G in Raman scattering of carbon nanotubes and natural solid organics seem to reflect not only structures and performance of carbon nanotubes but also thermal evolution of carboniferous solid organics in geological samples, and temperature and pressure conditions for experimental samples, so attracting extensive attention from the academic communities in the 7] reported the relationships between Raman inter-peak interval (D-G) and peak height ratio (D/G) of pyrolytic products of bitumite and kerogen and maturation of samples, or the temperature and pressure conditions for experimental samples. These authors concluded that