To study the effect of meteorological factors on urban traffic safety, a total of 2,602 traffic accidents with casualties occurring in the urban area of Nanchong City from January 2010 to December 2018 with 3 287 d were selected as the analysis samples, which were divided into flood season and non-flood season. The meteorological information was used for factor analysis respectively, and the factors were used as independent variables to establish the probability model of casualties traffic accidents caused in flood season and non-flood season. According to the test, the accuracy rate of non-flood season is 77.8%, and the accuracy rate of flood season is 63.8%. The rainfall factor has an impact throughout the year, which has the largest impact on traffic safety.In flood season, the increase of relative humidity is easy to increase the risk of traffic safety;High temperature weather reduces the probability of fatal traffic accidents;In the non-flood season, wind force factor is very likely to affect the occurrence of traffic accidents, followed by humidity factor, visibility factor, sunshine factor, and finally temperature factor.Compared with the flood season, meteorological factors in non-flood season have a more significant impact on traffic accidents.