Abstract: Based on the 1961-2007 meteorological data of Haikou City and its urbanization level in 1989-2007, this paper studied the climatope change and its relations with city development of the City. In 1995-2007, the mean annual air temperature in Haikou had an obvious increase, with an increment of 093 ℃·a^-1,while the mean annual relative humidity decreased obviously, with a decrement of 3% per year, compared with those in 1961-1990. Both the mean annual air temperature and the mean annual relative humidity had significant correlations with the urbanization level of Haikou, suggesting that urbanization could better explain the recent 20 years variation of climate elements in Haikou. The city development of Haikou not only changed the climatope elements, but also affected the air quality, making the frequency of acid rain increased, and the mean annual acid rain pH value decreased.

Key words: urbanization, air temperature, relative humidity, acid rain, Haikou, winter wheat sowed in spring, sowing date, photosynthetic efficiency, chlorophyll fluorescence parameter, grain yield.