The features of VDRAS products at the initial stage of thunderstorms during the 2008 Olympic Games are analyzed. It is concluded that collision among gust fronts can cause thunderstorms. The strong temperature gradients of VDRAS mean that a gust front will be separated from its major cell. Meanwhile, the intensified cold center means that the thunderstorm will develop. The VDRAS products are verified by means of the wind profile and AWS (Automatic Weather Station) data from Haidian. The results indicate that the wind direction of VDRAS from 0.18 to 1.6 km of height were the same as the profile, but the wind speed was smaller. Wind direction and wind speed from 1.6 to 2.8 km were the same as the profile. The wind direction of VDRAS from 2.8 to 3.5 km was also the same as the profile, but the speed was sometime smaller. In addition, the temperature of VDRAS was about 3 to 4 ℃ higher than that of AWS.