This study has been conducted to survey the perennial plants diversity in the Ibex reserve, located at the middle of Saudi Arabia, about 180 Km south from the Riyadh city. Analysis of the perennial plants of the Ibex protectorate resulted in identification of six major plant communities. Haloxylon salicornicum community was the major plant community in Ibex protectorate, showing a relative importance of 140.4%, followed by Rhazya stricta (115.6%), Ziziphus nummularia (115%), Acacia tortilis (113.7%), Rhanterium epapposum (109.7%), and Calotropis prosera community (102.8%), respectively. In addition, 62 perennialspecies, representing 34 families, were recorded in Ibex reserve. The largest family was Poaceae, represented by six species, followed by Mimosaceae (five species), Capparaceae (four species), Asteraceae (three species), Lamiaceae (three species), Rhamnaceae (three species), Zygophyllaceae (three species), Boraginaceae (two species), Brassicaceae (two species), Cucurbitaceae (two species), Scrophulariaceae (two species), and Urticaceae (two species). Seven families were represented by only one species; examples include Acantheaceae, Amaranthaceae, Apocynaceae, Cistaceae, and Convolvulaceae. The study demonstrated high perennial plant diversity of Ibex reserve and abundance of many plant species that were deteriorated in other places of the country due overgrazing and social behavior in Saudi Arabia.