Abstract: The observation of radiation of different wave length was conducted in the urban and rural areas of Kunming City. The main results on clear days obtained in this paper are summarized as follows.(1)In the urban area, the fluctuation of radiation of different wave length are larger in the urban area due to strong effect of pollution. The radiation (difference and ratio between urban and rural areas) is lesser in the urban than in the rural areas. The difference is outstanding in the morning when the pollution is string.(2)On the city of low latitudes and in plateau,on clear days of winter,the percentages of different wave length radiation in global radiation are different in the morning and in the afternoon.In the urban and in the rural areas, the percentages are different too. The difference is outstanding in the morning (because the pollution is strong). (3)At day time, in the morning and in the afternoon, there are difference in the total, the percentage and the ratio of radiation of different wave length between the urban and the rural areas.