Abstract: An improved SDS method，suitable for extracting genomic DNA of Actinidia young leaves，was established. Based on this result，an orthogonal design and a factor analysis method were combined to optimize the SRAP-PCR reaction system of Actinidia. The results indicated that the optimum concentrations of each component in the 20 μL reaction system included：DNA（40 ng ? μL-1）1 μL，Taq Polymerase（5 U ? μL-1）0.2 μL，dNTPs（2.5 mmol ? L-1）1.4 μL，primer（10 μmol ? L-1）1.5 μL，Mg2+ （25 mmol ? L-1）2.0 μL，10× Buffer 2.5 μL，ddH2O 9.9 μL. The genetic diversity and relationships of 32 kiwifruit varieties were analyzed based on this PCR reaction system. Fourteen SRAP primer combinationsgenerating a total of 275 bands，and the polymorphic bands were 100% for all primer sets. The results showed that SRAP could be as an efficient technique to assess genetic diversity for Actinidia. The dendrogram showed that all varieties could be divided into four clusters at the similarity level of 0.73，that including A. chinensis，A. deliciosa，A. melanandra，and A. eriantha. The relationship between A. chinensis and A. deliciosa，A. deliciosa and A. melanandra is close，whereas A. chinensis and A. eriantha is distant.

Key words: Actinidia, SRAP marker, system construction, genetic relationship