In order to improve the ability to use the products of T639, the synoptic verification on its mediumrange forecasting in 2010 spring is made in comparison with the NWP of ECMWF and Japan models. The results show that the three models have good performances in the aspect of predicting the largescale circulation evolution and adjustment in Asian middle and high latitude areas. As a whole, the ECMWF model is the best in forecasting most weather systems compared with the T639 and Japan models. Taking the sandstorm process during the period of 19-22 March as a case, it is found that Japan model is more effective than the other two models in the mediumrange forecasting of strong surface wind, which causes this sand and dust weather process.