At present, the global climate and environment change and its ecological response is one of the focuses that scientific circles pay close attention to. Since the discovery of the Antarctic ozone hole in the end of the 20th century, scientific circles has carried out a series of researches on issues of ecological and climatological effects caused by ozone reduce and surface ultraviolet radiation increase. In this paper, using the radiation transfer model simulation and actual observation, we theoretically analyze the variation characteristic of solar ultraviolet radiation in Kunming, and discuss the impacts of different factors on ultraviolet radiation, such as ozone, solar zenith angle, geographical latitude, sea level elevation and cloud. Among them the cloud has the special impact on ultraviolet radiation. Due to the uncertainty of the cloud, it is difficulty to describe the influences of solar ultraviolet radiation quantitatively. So we utilize model simulation and ground-based thermal infrared survey to analyze and research some characteristics of the cloud. Based on the interrelation of ultraviolet radiation and climate change, we consider the synthetically influence of many kinds of factors on the surface ultraviolet radiance and draw the following conclusions:1.The climate change in Yunnan has a heterogeneous structure in temporaldistribution, which indicates that the climate is a kind of chaos phenomenon.Factors, such as sea level elevation, geographical latitude, time series length andregional range, have closer relations with fractal value of climate system.2.The solar ultraviolet radiation at shorter wavelength drops violently with therising of the latitude and change tardiness with the increase of the wavelength,which is mainly in that the ultraviolet radiation at shorter wavelength is easierto cut down by the atmosphere, and in higher latitude the ultraviolet radiation isweakened greater.3.The interaction of cloud and solar ultraviolet radiation relates to cloud amountand cloud type. It is not as we thought that the surface ultraviolet radiationreduce with the cloud amount increased. In fact there is a trend of fluctuating.Different cloud types play important roles on solar ultraviolet radiation, someare weakening and some are enhancing.4.The daily ultraviolet radiant variation is quite regular, which shows obvioussinusoidal wave curve. The radiation reaches its maximum at afternoon, and itshows obvious positive correlation with the solar zenith angle.5.Total ozone column has an obvious negative correlation with solar ultravioletradiation flux .It can influence the surface ultraviolet radiation strongly. Onclear day, stratosphere ozone is the main influencing factor on ultravioletradiation variation.6.By model and actual sounding data, we calculate and analyze the relation of thesurface temperature, dew-point and brightness temperature.Key words: Climate change, ultraviolet radiation, ground-based observation, model research, cloudAbstract At present, the global climate and environment change and its ecological response is one of the focuses that scientific circles pay close attention to. Since the discovery of the Antarctic ozone hole in the end of the 20th century, scientific circles has carried out a series of researches on issues of ecological and climatological effects caused by ozone reduce and surface ultraviolet radiation increase. In this paper, using the radiation transfer model simulation and actual observation, we theoretically analyze the variation characteristic of solar ultraviolet radiation in Kunming, and discuss the impacts of different factors on ultraviolet radiation, such as ozone, solar zenith angle, geographical latitude, sea level elevation and cloud. Among them the cloud has the special impact on ultraviolet radiation. Due to the uncertainty of the cloud, it is difficulty to describe the influences of solar ultraviolet radiation quantitatively. So we utilize model simulation and ground-based thermal infrared survey to analyze and research some characteristics of the cloud. Based on the interrelation of ultraviolet radiation and climate change, we consider the synthetically influence of many kinds of factors on the surface ultraviolet radiance and draw the following conclusions:1.The climate change in Yunnan has a heterogeneous structure in temporaldistribution, which indicates that the climate is a kind of chaos phenomenon.Factors, such as sea level elevation, geographical latitude, time series length andregional range, have closer relations with fractal value of climate system.2.The solar ultraviolet radiation at shorter wavelength drops violently with therising of the latitude and change tardiness with the increase of the wavelength,which is mainly in that the ultraviolet radiation at shorter wavelength is easierto cut down by the atmosphere, and in higher latitude the ultraviolet radiation isweakened greater.3.The interaction of cloud and solar ultraviolet radiation relates to cloud amountand cloud type. It is not as we thought that the surface ultraviolet radiationreduce with the cloud amount increased. In fact there is a trend of fluctuating.Different cloud types play important roles on solar ultraviolet radiation, someare weakening and some are enhancing.4.The daily ultraviolet radiant variation is quite regular, which shows obvioussinusoidal wave curve. The radiation reaches its maximum at afternoon, and itshows obvious positive correlation with the solar zenith angle.5.Total ozone column has an obvious negative correlation with solar ultravioletradiation flux .It can influence the surface ultraviolet radiation strongly. Onclear day, stratosphere ozone is the main influencing factor on ultravioletradiation variation.6.By model and actual sounding data, we calculate and analyze the relation of thesurface temperature, dew-point and brightness temperature.