Abstract:Gladiolus hybridus Hort is one of the world famous cutting flowers.Because it is a pure exotic species, so there is no a uniform international classification method.It is classified mainly by biological characteristics,but is affected by environment deeply.Isozyme as the product of gene, can be used for identification and classification of gladiolus species, but there are some differences in different organ tissue within different time. however, molecular marker techniques is not affected by environment and different period of organ and tissue, stable transmissibility and simple analysis, which are widely used in flowers variety classification. RAPD analysis was applied in the study the classification and genetic relationship of 26 cultivars of G. hybridus Hort.Thirty-three arbitrary primers screened from 520 primers were used for further PCR and diversity analysis.A total of 206 RAPD sites were detected with a mean of 6.24 fragment amplified for each primer.A total of 185 polymorphic DNA fragments were detected among all the 206 amplified fragments,which accounted for a high level of 89.8% of all and could be used for identification of different cultivars.The result revealed that the germplasm resource of G. hybridus Hort cutting flower cultivar had a narrow genetic base on molecular level, some genetic relationship existed in summer large-flowers of G. hybridus Hort varieties.