Studies on land-use and land-cover change are important in rural, suburban, and urban areas. Classifying and analyzing land-use types during different periods clarifies the drivers of landscape change. This study applied 4-period land-use data in Dadu Hill to analyze changes in total landscape and individual land-use type. The result of this study showed that the total area of forest land and agricultural land gradually decreased, while that of developed land and grassland gradually increased. Forest land became grassland, and agricultural land became developed land. The area of forest land was 2,305.5 ha in 1977 and 808.3 ha in 2002, representing a 1,497.2 ha decrease. The area of agricultural land was 5,893.6 ha in 1977 and 4,274.6 ha in 2002, representing a 1,619 ha decrease. Furthermore, the area of developed land was 2,473.2 ha in 1977 and 3,851.4 ha in 2002, representing a 1,378.2 ha increase. Finally, the area of grassland was 434.4 ha in 1977 and 1,755.9 ha in 2002, representing a 1,321.5 ha increase. This study also compared its findings with the previous literature and concluded that the most likely explanations for the changes were forest fires and human construction. Forest fires led to forest land reverting savanna and grassland, after which savanna once again reverted to grassland. Agricultural land became developed land mainly through the Taiwanese economy evolving from being agricultural to industrial.