Based on the data of daily meteorological elements and traffic accidents during from 2010 to 2012, a comprehensive analysis is made. Results show: in Zhangjiagang, there exists relationship between traffic accidents and meteorological phenomena, such as meteorological elements as seasons (solar terms), strong wind, rainfall, snow cover, visibility, and temperature. The weather impacts road traffic safety not only through objective road traffic conditions，but also driver’s psychology indirectly. If weather forecast can be paid enough attention, the probability of traffic accidents can be significantly reduced.