Savanna ecosystems cover one fifth of the earth’s usable land and are home to billions of people and species. The ecosystem is threatened by human activities to a large extent, for instance, by grazing livestock, agriculture and fire management. In this case, it is necessary to detect the historical savanna changes in order to find out the past savanna distribution, current ecosystem change phenomenon and change tendency in the future. This research mainly focuses on the detection of savanna ecosystems in Belize, which is a country located in Central America. The distribution of savanna ecosystem in Belize covered over 2,021 km^2 in 2001 but now only covers 1,685.10 km^2 of that country. Therefore, it is necessary to find out how the savanna has changed by visually comparing the savanna ecosystems of remotely sensed images from different years based on the map produced in ArcGIS and ERDAS (Meerman, 2011). After the visual detection, a paired sample t-test and a box plot will be used as evidence to prove the detections. The result of this research shows a total change in the hectare coverage of savanna from 1980 to 2011.