Abstract:In the present study,a primer-pair for the amplification of rbcL433bp fragment was designed.In order to find out whether this primer-pair can be used as inner positive control for PCR detection of genetically modified ingredient in most plants,it wqs used to amplify DNA from 23 various plant species including monocotyledon(Allium cepa,Triticum aestivum,Zea mays,Oryzasativa),dicotyledon in Archichlamydeae(Brassica oleracea,Brassica pekinensis,Glycine max,Vigna unguiculata,Arachis hypogaea,Daucus carota,Apium graveolens,Spinacia oleracea,Cannabis sativa,Gossypium hirsutum)