Abstract: Study on genetic differentiation of 28 accessions thick-walled and thin-walled Dendrocalcamus sinicus was anaylyzed by using RAPD markers. Out of 88 RAPD primers, 17 primers with good reproducibility and clear ribbon were selected for RAPD markers. 131 loci were identified totally, 118 of which were polymorphic. The ratio of polymorphism was 90.08%. Polymorphism of thin-walled type was higher than that of thick-walled type. The genetic differentiation coefficient of both types was 0.154 6. Most of the thin-walled and thick-walled types were respectively grouped into one class by cluster analysis (UPGMA). It was proved that there were obvious differences between the thick-walled and the thin-walled D.sinicus in DNA.