The natural forest located across central Africa from Gambia (West Africa) to Ethiopia (East Africa) is believed to break the expansion of the great Sahara Desert towards the southern and south eastern Africa, as a green belt. However, natural and anthropogenic factors are challenging the existence of the forest. Thus, this study was conducted to investigate the spatio-temporal dynamics, threats and sustainable management options of the green belt forest (GBF) located in Ethiopia. Satellite imagery was used to assess the GBF cover dynamics between the year 1980 and 2020 using ERDAS IMAGINE software. ArcGIS software was used for spatial analysis and mapping. Field observation, focus group discussions, and questionnaire based interview were used to collect the required data and SPSS software was used for analysis. The result showed that farmland increased from 32% (in 1980) to 52% (in 2020), whereas, the GBF cover decreased from 58% (in 1980) to 39% (in 2020), with the overall classification accuracy and kappa coefficient of 86% and 81%, respectively. Re-settlement, large-scale agricultural investment, charcoal production, fuel wood, and road construction were among the important threats causing the GBF reduction. Investors, settlers, migrants, residents and day-workers are agents of the GBF cover reduction. To minimize deforestation and sustainably use the GBF local bylaws, delineating and keeping the GBF from human interferences, building awareness, enrichment plantation, and alternative firewood sources were identified as management options. Therefore, to maintain the GBF and break the expansion of the Sahara Desert, governmental and non-governmental organization and the local community ought to apply the recommended GBF management options.