Abstract:The diseased samples of banana infected with CMV(Cucumber mosaic virus) were collected and a nucleic acid sequence based amplification(NASBA) detection system was developed.The specific primers were designed according to the high conserved region of RNA 2 sequence of CMV subgroupⅠ.The 310 bp specific amplification product was obtained in positive sample determined with 5% agarose gel electrophoresis.The 11 different banana samples were analyzed with NASBA and RT-PCR to find out reliability of the me-thod,the former was demonstrated by dot blot with digoxigenin-labeled probe and had the similar results with RT-PCR.Further,the sensitivities were also identical and was equal to 100 pg.