According to the observation of Guangzhou Meteorological Observatory from 1961 to 2002,climatic characteristics and forming cause of haze in Guangzhou are analyzed. The results showed that in Guangzhou haze days was maximum in December and minimum in June,the haze days in autumn and winter accounted for more than 70 percent of annual total haze days. In general,annual haze days represented the increasing trend. The change of annual haze days could be divided into five stages,among which haze days from late 1970's to middle 1980's and from late 1980's to middle and late 1990's were increasing rapidly. Inter-annual change of haze days was associated with pollutant concentrations in the atmosphere,whereas monthly and seasonal distribution of haze days tended to be controlled by synoptic situation and weather conditions. Haze could decrease global solar radiation and reduce sunshine duration.