Prosopisjuliflora is one of the most invasive species in arid areas of Afar region and protected area of Awash national park. The invasion of P. julifloraincreased at alarming rate devastating forage and pasture abundance and diversity that makes livestock rearing difficult; which ultimately affects the Afar pastoral livelihoods. The study focused on the impact assessment of impact of P. julifloraon the forage and pasture diversity in the pastoral area of the region. Even though, the plant has several uses, it becomes out of control,deteriorates and reduced the diversity of forage and pasture species of the Region especially Amibara, Gewane and BuriMudaituWeredas by reducing their abundance, distribution and by changing grazing land ecosystem to prosopis thickets. This resulted in decrease in number of livestock per head of the pastoralists due to shortage of feed, decreased productivity of the livestock in terms of milk, meat and other products, migration of the pastoralists and their livestock to another place in search of feed source. Several control measures such as mechanical control, producing charcoal and collection of pods for feeding of the cattle has been implemented in the areas but lacks proper prevention and management methods of the plant. Thus, proper management and control of the invasive species and conservation of forage and pasture species are urgent issues for sustaining the livelihoods of the pastoral communities of the area.