To define the population dynamics of white back planthoppers Sogatella furcifera （Horváth） and the infection rates of southern rice black-streaked dwarf virus (SRBSDV) in the 4 counties in Jiangxi, i.e. Chongyi, Jinggangshan, Lianhua and Wan′an, the population dynamics of white back planthoppers under the insect luring light and in the field were determined through insect luring light observing and field sampling, and the infection rates of white back planthoppers in different periods were determined using RT-PCR method. The results revealed that the regulation of the population dynamics of white back plant hoppers and the infection rates tended to be the same.That is the infection rates were much higher in the high-incidence periods. The peak period of white back planthoppers in Chongyi and Wan′an was earlier, which was around July 28th, followed by Jinggangshan around August 8th. The peak period in Lianhua was the latest in the four counties, which was around August 18th. A conclusion was drawn that white back planthoppers with SRBSDV came into Jiangxi Province from the Southeast and then went to the neighboring provinces.