[Objective] The aim of research was to detect the genetic variation of Dendrobium by RAPD molecular marker.[Method] With 4 different varieties of Dendrobium and 1 variety in vitro as materials,after DNA extraction,10 bp random primers was used for RAPD detection of genetic variation.[Result]Burana Greenand Pink Thamond 2 varieties not found genetic variation;the genetic variation rate of BigPanda was 3.3%,the genetic variation rate of Thailand White was 23.3%;the genetic variation rate of Red Sonia in vitro...