Abstract: Viola tuberifera, which is endemic to the Qinghai-Tibetan Plateau and its adjacent region, is a typical dimorphic cleistogamous plant, and the taxonomical position of V.tuberifera is still controversial. We analyzed the morphological variation of leaves from the digital specimen and three sympatric natural populations of V.bulbosa and V.tuberifera. The PCA analysis of digital specimen indicated that all the samples were divided into two clusters, represented for V.tuberifera and V.bulbosa, respectively. The PCA analysis of sympatric natural populations showed the same results. The parameters reflected the characters of leaf apex and base, such as ΔW, AL, BL and LWR, are relatively lower variation within and among populations of V.tuberifera and V.bulbosa, but the variation of these parameters between V.bulbosa and V.tuberifera is significant(P<0.01). V.tuberifera and V.bulbosa should be treated as different taxon, and indicating the leaf morphological characters can be used in the classificatiopn of V.tuberifera and V.bulbosa.