Abstract: Remote sensing nighttime light combined with surface observational data was used to investigate the influences of urbanization on climatic conditions, air pollutant concentrations and haze formation. The results showed the obvious urban climate effects of “dry” and “heat” island, low atmospheric humidity and low visibility. From 1980-2010, the annual average temperature in Hangzhou increased 0.70 ℃/10 a, the average wind speed decreased 0.11 m/(s·10 a) and the visibility rate decreased 1.40 km/10 a. As compared with Lin'an, Hangzhou's values were higher by 0.41 ℃/10 a, 0.06 m/(s·10 a) and 0.92 km/10 a over the same period. Urbanization also changed the air pollutant composition. The monthly mean PM_2.5/PM₁₀ was 0.52-0.69 in Hangzhou, which was much than the values in Lin'an (0.45-0.59). Additionally, the concentrations of precursors of secondary aerosols such as NO₂ and SO₂ in Hangzhou were also higher than those in Lin'an. The annual mean concentration of NO₂ was higher than that of SO₂ in Zhejiang Province. In Lin'an, it was 5.8 μg/m³ higher, while it was 21.0 μg/m³ higher in Hangzhou City. Also, the ratio of NO₂ to SO₂ concentration in Hangzhou City (1.70) was higher than that in Lin'an County (1.57). Under the situation of inefficient model of economic growth, the effects of urbanization on climate and pollutants promoting haze formation explain the agreement between annual haze days and nighttime light on the spatial distribution and decadal variation trend in Zhejiang Province. Serious haze pollution mostly occurs in the northern part and the eastern coast of Zhejiang Province, and the Jinqu Basin region where urban development is fast and nighttime light is intensive. Furthermore, two dramatic changes in number of annual haze days corresponded to the reform and opening-up as well as the intensification of urbanization after 2000. A close relationship between annual haze days and total grey value of nighttime light was found; the correlation coefficient reached 0.99, which is higher than that of GDP, non-agricultural population and other factors. The study shows that extensive urban development is the primacy cause of more serious air pollution in Zhejiang Province.