Rice dwarf outbreak caused by Southern rice black-streaked dwarf virus(SRBSDV) was occurred in Hunan province in year 2010. To determine the natural hosts of SRBSDV, cereal crop and weed samples in or around the infected rice fields from different counties of Hunan were collected and detected by RTPCR with a patented primer pair. The results showed sorghum (Sorghum bicolor), wild oat (Avena fatua L.) and goosegrass (Eleusine indica) were the new natural hosts of SRBSDV.