Abstract: Studying and mastering the meteorological factors influencing highway visibility and its correlation are the basis of highway visibility forecast. The weather phenomena influencing highway visibility mainly include rain, snow, fog, haze, dust etc. In this study, daily surface meteorological observation data from the meteorological stations at a distance of 5 kilometers a (from September in 2002 to March in 2010), and hourly visibility and surface meteorological observation data from the 2413 automatic meteorological stations (from January 1 to December 31 in 2008)are utilized. the characteristics of the temporal and spatial distribution of rain, snow, fog on the national highway and the relationship between the 1 hour rainfall and visibility are studied and analyzed be means of statistical methods. (1) Compared with other weather phenomena, the effects of fog on the visibility is the largest, and the low visibility range resulted from fog effect is mostly below 200 m, the frequency distribution of rain, snow and dust in time is uniform, and the influence of low visibility ranges in 500~1000m. (2) In each area of China, the main weather phenomenon that affects low visibility of highway are different. Basin in the south of Xinjiang and Inner Mongolia and other places are more influenced by dust; Northeast, North China, Tibet and other places are affected by rain and snow; South and southeast of Tibet are mostly influenced by rain. (3) The higher frequency regions with low visibility caused by precipitation are mainly the Yangtze River Basin, south of the Yangtze River, Southern China and other places. At the same time, there is negative correlation between rainfall intensity and visibility, but not to lump together. (4) The probability of low visibility in the snow weather is higher than that in rainfall weather. For snow weather, low visibility of 200~500m occours commonly, and in the rain, the probability of the low visibility of <200m appears higher than the low visibility of 200~500m.