Beginning with the treatment of the police agency and its tedious changes and complex evolution in the Mt. Li-tung area, the paper attempts to study two types of aboriginal management facilities in Taiwan's mountainous region during the Japanese colonial rule-namely, the barrier defense lines and the stationary offices. It delineates their structures, real constructions, and the process of changes. It analyzes the similarities and differences of their locations, scales, deployments and actual buildings. In conjunction with on-the-spot investigation of Mt. Li-tung's barrier defense lines and stationary offices, the paper discusses the influences of such aborigional-management facilities upon the space structure of Taiwan's mountainous region. During the course of managing and pacifying the aborigines in Northern Taiwan's Tao-yuan and Hsin-chu mountains, the Taiwan Government-general changed its policy from the earlier barrier defense lines to the later stationary offices, which is microcosmic of the colonial government's 'opening up' and effective rule of Taiwan's mountainous region. In 1910, the Japanese rulers first erected the barrier defense line in the hilly area to not only contain and isolate the unsubdued aboriginals, but to also pave the way for extending their jurisdiction into the aboriginal region. Utilizing such policing facilities, they were able to divide up the hunting grounds, arable lands and tribal boundaries of the aborigines, and to also cut off communication among various ethnic and tribal groups. After smashing the aboriginal resistance, the Japanese colonial government continued to use the barrier defense lines for garrison, but soon began to install stationary offices among the major tribes. It used guile and other inducements to 'civilize' the aborigines while simultaneously built roads along the rivers and valleys, facilitating a transportation network among various tribes. By 1920, the stationary offices--which were charged to civilize and to guard the aborigines, had replaced the barrier defense lines. And as the Japanese garrison forces concentrated at the newly established stationary offices, the garrison roads gradually turned into the backbone of the vast mountain region while the stationary offices ultimately evolved to become the nucleus of the newly restructured tribes. Such phenomena completely and drastically transformed the space structure of Taiwan's mountainous region.