Abstract:Citrus exocortis viroid (CEVd) causes an important citrus disease throughout the world. To date, variousmethods have been developed for detecting this viroid. One-step reverse transcrip tion and polymerase chain reaction (RT-PCR) has been approached to detect CEVd. Compared with biological indexing and detection by sequential polyacrylamide gel electrophoresis (sPAGE) , detection by One-step RT-PCR was more sensitive and quicker than that by other methods, overcoming the detection difficulty derived from low viroid concentrations in winter and spring. Large number field trees were detected by the One-step RT-PCR method.