Non-destructive Raman spectroscopy was applied to three kinds of porcelain glaze samples: (i) Guan wares of Song Dynasty; (ii) Imitated Guan wares; (Both (i) and (ii) are from the Palace Museum (Beijing, China) collections); (iii) Porcelain shards are collected from the Xiuneisi kiln site which is one of two excavated Guan ware imperial kilns in Hangzhou, the capital of the Southern Song Dynasty. Raman spectra of the glassy phase network were used to discuss the composition and firing temperature of the glaze. The index of polymerization (Ip) is strongly correlated with the firing temperature and the composition of the glaze. According to the Ip values of the glaze, those Guan wares (i) can be classified into three groups. The provenance of Guan wares (i) was discussed by comparing the Ip values to imitations (ii) and shards(iii). The study of classification and provenance are also supported by the X-ray fluorescence data. The Ip values of several recently prepared glazed samples of known firing temperature were measured to build empirical relationship between the Ip value and the firing temperature. Based on the relationship, the firing temperature of the Guan ware glazes was at 1170-1300°C.