This survey was conducted from April of 1987 to January of 1989. Total 24 species of mammals were recorded from the Guanshan area of Yushan National Park. More than half of recorded mammals in Taiwan were able to find from this survey. Endemic specise were Macaca cyclopsis, Rattus culturatus, Apodemus semotus, Mogera insularia and Soriculus fumids. Based on the traces left by mammals in this area, white face giant flying squirrel possesed the highest frequencies (77 times), followed by Formosan rock monkey (69 times). As for habitat analysis, 37.85% traces were found from mixed forests, followed by 34.41% from broad-leaved forests. Almost no animal was found from deserted farmland. The correlations between animals and vegetations among 6 surveyed plots were analyzed. Habitats of Formosan Serow (Capricornis crispus swinhoei) were discussed in detail. One set of small Chinese civet (Viverricula indicu pallida) skeleton was found from the coniferous forest near Jean-Jean Bridge. Meantime we found a large population of Macaca cyclopsis in the deserted YaKo lumbering trail.