Utilizing the theory on calamity study and taking pasture of Qinghai as an example, the factors inducing snow disaster in Qinghai-Tibet plateau are analyzed. Based on the Geographical Information Database (GIS), a synthetical identification snow model is constructed to monitor quickly the snow disaster after a snow, and then, the trend of snow disaster is forecasted dynamically, finally the estimation to disaster is conducted. The results show that during the processes of forming the snow disasters, in addition to the function of snow cover, the fragility of environment suffering disaster and sensitivity of carrier disaster play important roles. The advice which protect pasture and strengthen animal husbandry is given to decrease the damage of snow disaster. At last, using the synthetical forecasting model of snow disaster, the snow disaster forecast in Qinghai is made. The result shows that the model has potential value of application.