The survey of the mammal fauna found 24 species (bats are not included) in the Dongpu area of Yushan National Park. Rodentia made up the majority of the mammal fauna. Other mammals with higher encounter rates were the Formosan rock-monkey (Macaca cyclopsis), the Formosan reeve’s muntjac (Muntiacus reevesii micrurus), the Formosan wild boar (Muntiacus reevesi micrurus), the goat, the Formosan weasel marten (Mustela sibirica davidiana), the Formosan ferret-badger (Melogale moschata subaurantiaca), the Formosan gem-faced civet (Paguma larvata taivana), and the Formosan sambar (Cervus unicolor swinhoei). In addition, traces of bears were discovered only twice, and a small Chinese civet (Viverricula indica taivana ) was suspected to be present (footprints). The total biomass was greater in the Chenyoulan River watershed than in the Shalisian River watershed. The goats were the most in population in the Yushan Mountain Range area. The degree of disturbance caused by forest roads was a significant factor affecting the inhabitation of animals. The distribution of ungulate species at high altitudes varied significantly. Goats preferred a different slope grade with an average of 29.77 degrees when compared to other animals. The Formosan wild boar, the Formosan reeve’s muntjac, and the Formosan rock-monkey mostly co-inhabited in broad leaf forests. Though easily found on mountain ridges, the Formosan sambar was only found in the Guangao area. From 1988 to 1989, a survey of deer feces was conducted to estimate the deer population in the study area. The population density of the Formosan reeve’s muntjac was 156 individuals per km2 during fall and winter; and 66 during spring and summer. The population density of the Formosan sambar was estimated using the Reverse Line Intercept method, indicating that there were 2.04 individuals per km2. The population estimated was a drastic increase when compared that of the estimation from the annual report for the second year survey.