Abstract: The aim of this study was to develope species-specific molecular marker for identification of Gynostemma pentaphyllum and that with their adulterant Cayratia japonica,in order to avoid adulteration that affects the quality and quantity of G.pentaphyllum The first,twenty 10-bp random primers were picked out from more than 2000 random primers and then divided randomly into four terms that were consist of five random primers.The second,Genomic DNAs of seven G.pentaphyllum from different places in Guangxi,China,were amplified using a PCR-based RAPD technique and the same manipulation was repeated to confirm species-specific DNA fragment which was the one of RAPD produts.The last,with getting the message of cloning and sequencing of the RAPD products,the species-specific primer was designed and synthesized to amplify fresh leaves and dried medicines of G.pentaphyllum,Cayratia japonica and so on.As anticipated,the genomic DNAs of G.pentaphyllum were only amplified a band and that of others were amplified no band,using the species-specific primer and so sequence-characterized amplified region(SCAR) marker were developed.The SCAR marker are potentially useful for the identification of G.pentaphyllum in Guangxi and their adulterant Cayratia japonica,also other plants.In addition.This is the first report of species-specific SCAR development in G.pentaphyllum.