Abstract： The genetic diversity of 20 Zingiber officinale cultivars was studied by RAPD. Twenty five primers were screened from over 200 arbitrarily primers, and a total of 171 bands were amplified, DNA bands were amplified from100～3 500 bp, among which 111 were polymorphics (64.91%). The average number of DNA bands produced by each primer were 6.84. The J coefficient was worked out by NTSYS-pc softwarefrom amplified bands and were clustered. Based on UPGMA, a DNA molecular dendrogram was established for 20 Z. officinale cultivars in China. When the coefficient was 0.67, these 20 cultivals were divided into four groups, GroupⅠ, Ⅱ, Ⅲ and Ⅳ. GroupⅠwas divided into section A, B and C, and GroupⅣ was divided into Section D and E. Meanwhile, Section A was divided into Subsection A1 and A2, while Section B was divided into Subsection B1 and B2. The coefficient in each subsection was very high, which suggested that the relationship among subsections was fairy close, but some genetic difference existed.
