The characters of ultraviolet radiation in Nanning city are discussed, its relation with global radiation and cloudage is also analyzed. It points out that the character of ultraviolet radiation in Nanning varies obviously in different seasons,it is the strongest in summer and the weakest in winter. The ultraviolet radiation becomes stronger since April and becomes weaker since October every year and is the strongest between 12 o'clock and 14 o'clock everyday. Its correlation coefficient with global radiation is 0.67 and the correletion with cloudage in some months is obvious.The daily varying curve is the most smooth in sunny days,worse smooth in cloudy days,the worst smooth in little cloudy days.