By using the daily snow data,monthly precipitation and monthly mean temperature data of 19 meteorological stations in high altitude pastoral areas of Tibet plateau from October 1979 to April 2013,and based on the snow disaster index of snow depth and snow last days,the climate change characteristics of different grade snow storms and the impact of changes in temperature and snowfall of snow storms were analyzed. The results show that the period from November to the next February is the high incidence of snowstorms in the Tibetan plateau and the disasters are very severe,with the big probability of moderate or above snowstorms occurring throughout the year,which accounts for 54% of the total number of stations; The snow disaster change showed a decrease trend since 1979,but there exists a decadal variability,which is characterized by higher volatility in 1980-1997 and show a significantly reducing trend since 1998-2007,since then up slightly,the point mutation is in 1999 and 2008; The correlation between temperature and snowstorm is higher than that of snowfall,the temperature is significantly warmer,but the snowfall changes are not obvious,so the temperature plays a decisive role in the snowstorm climate change. The relationship between the atmospheric circulation system and the snow disaster was analyzed,and it is concluded that it is prone to snow disaster when the west wind belt and the eastern hemispheric vortex become stronger and the east Asian trough and the subtropical high become more west,and vice versa. The variation trend and mutation point of the western wind belt south branch trough and the eastern hemispheric vortex are very consistent with the change trend and mutation point of the snow disaster in the Tibetan plateau,which is a possible cause of the snowstorm changes in the Tibetan plateau.