Objective This study was carried out in order to analyze genetic diversity in plants of Dendrobium Sw. and compare the marker index (MI) between SRAP and RAPD markers. Methods Using 40 SRAP primer combinations and 36 RAPD primers,the genetic diversity of the materials in Dendrobium Sw. was amplified. Results A total of 1 977 loci were generated by 40 SRAP primer combinations,of which 90.2% was polymorphic and the genetic similarity (GS) ranged from 0.330 2 to 0.789 2. As for RAPD,281 bands were obtained,in which 87.1% was polymorphic,and the GS was from 0.494 2 to 0.773 1. There were some differences existing in the two cluster results revealed by SRAP and RAPD markers,they were as follows:compared to that of RAPD,the result of SRAP could more comfortably reflect the kinship and geographical origin,simultaneously conform to the traditional classification. For the experiment materials,SRAP (16.46) got an MI value 4.5 folds higher than that of RAPD (3.67),which meant SRAP markers were more effective in detecting genomic polymorphisms in the plants of Dendrobium Sw. Conclusion These results show that SRAP and RAPD could be applied to detecting genetic diversity analysis of plants in Dendrobium Sw. SRAP Also shows great superiority and advantage in this study.