Abstract: Using the daily snow cover data from 189 meteorological stations to the west of 105°E in China for the period 1960-2004, and the daily snow depth data retrieved from the passive microwave remote sensing data (SMMR and SSM/I) in 1981-2004, types of the snow cover are classified by the interannual variability of snow cover days (IVSCD) and by snow cover days (SCD), and the differences between the two methods of dividing snow cover types have been analyzed. Furthermore, a new comprehensive indicator combining the above two elements (IVSCD and SCD) has been established. The results show that, based on the observational data, 3 types of snow covered areas (including stable snow-covered areas, annual and non-annual periodic unstable snow-covered areas) are classified by IVSCD in western China. Stable snow-covered areas include northern Xinjiang, the Tianshan Mountains, and the high-altitude mountains in the eastern Tibetan Plateau, and, annual periodic unstable snow-covered areas are mainly located at the periphery of the southern and eastern Xinjiang Basin, the Hexi Corridor, northern Qinghai, the central and western Tibetan Plateau, the southern Tibet Valley, and the southeastern fringe of the Tibetan Plateau. In addition to the above mentioned, there are non-annual periodic unstable snow-covered areas. After abrupt change of climate, changes of snow cover types, as classified by IVSCD and by SCD, reflect increases in the stable snow-covered area in the eastern Tibetan Plateau and the amplitude of variations of snow cover in the desert and the low-latitude areas, respectively. In a large extent, satellite remote sensing data can compensate for data that is missing due to the scarcity of stations, and the types of snow cover classified by IVSCD are better in determining the characteristics of snow cover in western China, implying that there exists a close relationship with the topography as shown by these data. As classified by the comprehensive indicator, the distribution of snow cover types in western China has been more significantly influenced by the snow cover duration based on the observational data, and for the one based on the satellite remote sensing data the IVSCD is the major influencing factor.