Abstract: This paper is concerned with studies on leaf epidermis of the Campanulaceae in Heilongjiang Province by the light microscope and SEM. The results are follow:Ⅰ. Epidermal cell: According to the shape in surface view, epidermal cells can be polygonal, irregular and rectangular. Last one is always distributed on both surfaces of leaf margin, main veins and lateral veins. Anticlinal walls of polygonal cells are straight, and those of irregular ones undulate. In general, the variation in cell shape isn't obviously related to habitats.Ⅱ. Cuticular ornamentation: With different species, cuticular ornamentation is variable, especially in Adenophora tricuspidata A. DC. complex. For exampie: cuticular membrane of leaf epidermis of A. tricuspidaga is smooth, and of A. amurica Fu et Liu is longitudinal striation. So, cuticular ornamentation in the Campanulaceae is of diagnostic value.Ⅲ. Stomata: Stomata is ranunculaceous type. Stomata of A. polyantha Nakai is the biggest, and one of Codonopsis ussuriensis Hemsl. is the smallest.Ⅳ. Trichome: Length, distribution and density of trichome on leaf is significantly variable in response to varied enviromental conditions. It is important that variation of cuticular ornamentation on the trichome be used to distinguish different taxa. Cuticular ornamentation on the trichomes of Wallenbergine Endll. is smooth, and one of Adenophora is spiral or longitudinal striation.