Alpha and beta diversity and evenness were investigated along an elevational gradient in a mountainous region in East Black Sea Region of Turkey. Alpha and beta diversity indexes and Shannon’s evenness were significantly changed along the elevational gradient. The highest Shannon_Wiener and Margalef were found in Festuca lazistanica subsp. giresunica community. The highest Simpson’s index was found in Acantholimon acerosum community. Alpine grasslands represented by Festuca lazistanica subsp. giresunica community had the lowest evenness, while forest communities represented by P. orientalis-Rh. luteum community had the highest evenness. The highest beta diversity was found in Picea orientalis-Rhododendron luteum forest community, while the lowest beta diversity was found in Festuca lazistanica subsp. giresunica community. Organic matter, elevation and aspect were found to be the most significant factors by CCA analysis. While hemicryptophytes was found to be the dominant life form in studied in all different plant communities, therophytes was found to be lowest.