The performance of mediumrange forecasts is verified and compared for the T639, ECMWF and Japan models from March to May 2017. The results show that T639 and ECMWF models can predict the variation and adjustment of the atmospheric circulation over Asian middle and high latitude areas well. T639 and ECMWF models perform well in predicting the transition of temperature at 850 hPa, as they all have smaller biases for Southern China than for Northern China, but ECMWF model shows a better comprehensive performance than the other one. Taking the sandstorm process seen in 3-7 May as a case, we see that ECMWF model is most effective in mediumrange forecasting of the surface high pressure system which incurred the sandstorm weather process this time.