Rice black-streaked dwarf virus (RBSDV) and southern rice black-streaked dwarf virus (SRBSDV) are the main viruses which bring rice dwarf. However, the symptoms of these two viruses are highly similar and it is difficult to distinguish them only by field observation. To construct a fast detection method of these two viruses, the PCR reaction system and program were optimized from two aspects, ie. the mixing ratios of mixed primers and the annealing temperature. Finally,an exact,sensitive and fast one-step detection method was found. At the same time, the rice dwarf virus samples from Dayu County and Nanchang County in Jiangxi Province were detected with this method, and the results revealed that all of the 10 samples from Dayu County were identified as southern rice black-streaked dwarf virus with a detection ratio of 100%, 7 out of 10 samples from Nanchang County were identified as southern rice black-streaked dwarf virus with a detection ratio of 70%, and 3 out of 10 samples from Nanchang County were identified as rice black-streaked dwarf virus with a detection ratio of 30%.