Rice black-streaked dwarf virus, Rice stripe virus, and Southern rice black-streaked dwarf virus (SRBSDV) have been epidemic in large areas of China where rice is grown, causing significant losses of rice yield in recent years. These viral diseases sometimes occur in the same regions, and even in the same fields, making it difficult to detect and diagnose the viral pathogens. A set of primers specific to the genes encoding the capsid proteins of the three viruses were designed, and a multiple one-step reverse-transcription polymerase chain reaction protocol was developed. The method proved to be simple, rapid, and sensitive. It was used to detect the viruses in samples of rice, maize, small brown planthoppers, and white-backed planthoppers collected from different regions of China, showing that it is suitable for routine diagnosis. A simultaneous survey of the three viruses was further conducted by this method throughout Zhejiang Province, Eastern China. The results showed that both RBSDV and RSV had continued to spread and that the newly emerging virus, SRBSDV, was present in at least 27 counties or cities, suggesting that more effort is needed to monitor and control the threat from these three viral diseases.