Monitoring seasonal change of white-back rice planthopper, Sogatella furcifera (Horvath), collected by light-trap in Zhaoqing City, Guangdong Province, since 1979. The result showed that: The earliest date of collection was in March or April in these years. There were two population peaks in one year. The first peak in early rice was between the first ten days of May to the first ten days of July. The second peak in late rice was between the middle of September to the middle of October. According to the collections in the peak day, and 10 days average, the accumulative total of all days in early rice and late rice time, it was showed that: The occurrence of white-back rice planthopper was more serious from the late of 1970s to the middle of 1980s, however its occurence was more lighter in late of 1990s, even to the early years of the 21 century.