In order to protect the ecological environment of Xizang and understand the growth of forage,the 16-day synthetic MODIS data provided by NASA was used to predict the normalized vegetation index(NDVI)to better eval-uate the growth of forage by using the NDVI as the growth cover characteristic index of forage.Taking the NDVI in Naqu City as an example,the ARIMA and SARIMA models were used for prediction.The results showed that the SARIMA model had good accuracy in prediction and could better evaluate the growth of the forage grass.