Biodiversity is the wealth of life on earth which includes plants, animals, microorganisms, and the genetics they contain. Preserving biodiversity through genetic resources is important in anticipating extinction and as an effort to develop superior cultivars or races. Kepel plant is a typical plant of Yogyakarta and has beneficial ingredients for health. However, its existence is currently less, so it is necessary to preserve it through genetic resources namely DNA isolation. The success of DNA isolation requires good concentration and purity, so the purpose of this study was to optimize the isolation of Plant Kepel leaf DNA in terms of type and explant weight of DNA quality and quantity. The method used was an experiment and was arranged in a one-factor Completely Randomized Design (CRD) consisting of 9 treatments with 3 replications, resulting in 27 experimental units. The treatments used were the type of explants of young red leaves, young green leaves, and adult leaves with each type of weight weighing 0.1 gram, 0.2 gram, and 0.3 gram. The results of research was sample of red young leave weight 0,3 gram might be the best samples to produce highest yield of DNA.