Abstract: The taxonomy of Viola L. has been problematic due to its varied morphology in a large number of species with a wide distribution. To solve its taxonomic problem, leaf morphology and anatomy in eight Viola species from Yunnan, China were investigated using the microscope and paraffine section. The results showed that:（1）There were four leaf shapes grouped into the reniform, the hastate, the ovate, and the three-lobed types.（2）There were three types of uniseriately single-celled trichome, including the short-column, the medium-column, and the long-column, growing along the margins and veins of leaves.（3）The anticlinal wall of epidermal cells was the straight-arched, the sinuolate, and the sinuous patterns respectively. Most of the stomata were orbicular while some were elliptical, which comprised the paracytic, the diacytic, and the anomocytic patterns.（4）The outlines of mid-rib transverse section were divided into the equal and the unequal types based on the different sizes between the adaxial and the abaxial epidermis.（5）The shapes of cross section of the petiole were grouped into the elliptical, the sub-orbicular, and the circle patterns, with obvious adaxially lateral wings and ridges. The number of vascular bundles was one or three, with varied three outlines containing the round, the shallowly U-type, and the deeply U-type. It was showed that some selected features of morphoanatomy of leaf were much valuable for problematic species delimitation, including the leaf shape, the trichome, the epidermal cell, the outline of vascular bundle, and the shape of cross section of leaf and petiole.Additionally, it was supported that V. inconspicua, V. prionantha, and V. philippica should be treated as three independent species.