Woody plants such as Prosopis (henceforth referred to as Prosopis juliflora) are invading rangelands and threat to pastoral production. The study aims to assess (1) the spatial effects of Prosopis invasion on LULC (henceforth referred to as land use land cover) detections, and (2) the temporal effects of Prosopis invasion on LULC in Amibara and Awash Fentale districts of south Afar in Ethiopia. We used a combination of remote sensing data and field observations to analyze the effects Prosopis invasion on LULC dynamics for the patterns and dynamics for 31 years from 1986 to 2017 in the arid and semi-arid of Sothern Afar rangelands. The overall accuracy for 2017 was 84.9% with Kappa statistics of 0.82. In Amibara district, farmlands, water bodies, Prosopis, and grass land areas were increased during 1986-2017 by 1879 ha (10.8%), 1197 ha (55.6%), 3132 ha (99.0%), and 31,039 ha (22.0%), respectively. However, bare lands and wood lands areas were decreased by 1239 ha (56.7%) and 36,065 ha (49.9%) respectively. In Awash Fentale district, changes of land use/land cover types showed positive trends for farm lands, water bodies, Prosopis, and grazing lands by 4258 ha (81.4%), 1035 ha (97.4%), 2335 ha (97.0%), and 18,187 ha (25.8%) respectively in the same period. However, bare lands and wood land areas decreased by 59.78 ha (59.8%) and 51 ha (50.9%) respectively. If the present LULC change and the effects of invasion on LULC were to continue coupled with a drier climate, people’s livelihoods will be highly affected and the pastoral production system will be under increasing threat. Further study is suggested to investigate detailed drivers and consequences of changes.