Abstract: Based on the ultraviolet radiation observation data from August 2007 to August 2008 in Dalian, the seasonal, monthly and daily changes of ultraviolet radiation and the relationships with meteorological factors were analyzed. The results show that the ultraviolet radiation intensity is of seasonal characteristic in Dalian, which is strong in summer, followed in spring and winter. The diurnal variation has the same trend among different seasons, which is an approximately symmetric distribution at noon. The total sunshine duration, fourteen o’clock visibility and solar altitude angle are the important controls on the ultraviolet radiation intensity. At the same time, the effects of fog on ultraviolet radiation intensity were also analyzed. The ultraviolet radiation intensity forecast equations in every season were established by the stepwise regression method.