Abstract: Based on the synthetical analysis,the method of the grey incidence analysis of grey system is also used.The average proportion of the loss caused by snow disaster in 1985 and 1995 is chosen as referring series.Sever factors including air temperature and average precipitation from October to next April,days of accumulated snow,proportion of grassland degeneration,quantity of livestock,overloaded proportion of pastureland,amount of herbage stored for the winter are chosen as the comparing series respectively.The degree of grey incidence is also calculated.The results objectively reveal the relations between the loss of snow disaster and the factors and provide a scientific basis for the prediction and prevention of snow disaster in Nagqu.