To analyze the characteristics of 42 years haze days of Changsha, Hunan Province and the influence of meteorological factors on haze days, using the ground meteorological observation data from 1971 to 2012, results indicated that the key haze factors of Changsha are annual temperatures, warm days and nights, cold days and cold nights, days of wind condition with f≥5 m/s, days of wind condition with f≥10 m/s, days of rainfall no less than 0.1 mm. In most recent 42 years, annual temperature, warm days and warm nights increased significantly, which are positively correlated with significance of haze days. Instead, cold days and nights decreased significantly, which are negatively correlated with significance of haze days. Days of f≥5 m/s, f≥10 m/s and days rainfall≥0.1 mm decreased significantly, which are significantly negative correlated to number of haze days. The number of haze day significantly increased, and increase of number of haze days is attributed to climate warming, reduction of dilution diffusion capacity of wind conditions on atmosphere pollutants, and decrease in purification ability of the precipitation on atmosphere.