The Nan-Tzy-Shian River watershed area of Yushan National Park, the largest national park in Taiwan, comprises abundant natural resource and important habitats for endangered Formosan black bears (Ursus thibetanus). However, this area has also been one of the highly potential spots influenced by enormous tourism pressure. In order to monitor the wildlife resource through time, we adopted the sign account and camera trapping methods to evaluate the abundance and distribution of mammals during April–December 2004, and further compared our data with another study conducted in the same area in 1996. We identified 20 species of mammals, including small Chinese civet (Viverricula indica) and 5 rodent species, which were not recorded in the previous study. Although we did not record the once-occurred Formosan hare (Lepus sinensis), our study suggested that the abundance and distribution of common large mammals have increased and expanded. The result of meta-analysis of camera trapping data throughout Taiwan also indicated the extreme abundance and diversity of mammals in this area. However, with the evidence of illegal hunting, we highly suggest the importance of long-term wildlife study and consistent monitor program in this area.