Analyzing the genetic diversity by using the Randomly Amplified Polymorphic DNA (RAPD PCR) technique to identify seven genotypes selected of cacti were Ariocarpus kotschoubeyanus (Lem.) K. Schum, Gymnocalycium pflanzii (Vaupel) Werderm., Mammillaria elongata DC., Mammillaria erythra, Mammillaria grahamii Engelm, Mammillaria winterae, Stetsonia coryne (Salm- Dyck) Britton & Rose., the outcome has been detected ten primers rise from 25 primers with yield 390. The primer OPC-05 yielded a high number of DNA fragments, 53. The primer OPA-11 was characterized by a heist polymorphism percentage of 100 % and the lowest percentage of polymorphism by primer OPAD-17 was 25%, depending on the similarity matrix the UPGMA analysis was done. the phylogenetic dendrogram showed the studied taxa divided into two main groups at a similarity value of 0.025, the first group included six taxa divided into two clusters (A, and B) with a similarity value was 0.013, the first cluster (A) separated into two clades (AI, and AII), the AI  isolated G. pflanzii from other taxa, while AII divided to two-branched (1and 2), the (1)  contain  M. elongata, M. erythra, and M. grahamii with achieving closest genetic distance was 0.960, while (2) include M. winterae, S. coryne that have similarity average 0.831. The B group has only one genotype A. kotschoubeyanus which showed the highest molecular differences from other taxa, The results obtained from this study may be useful as a phylogenetic tool that can be combined with morphological, and anatomical features to make a better understanding of the systematic or taxonomy of cactus taxa.