The resource survey of wildlife in eastern area Yushan National Park have been proceeded for many years and got more information such as the composition and habitat use of wildlife. However, the plant structure, vegetation types, species diversity and the distribution of dominat species were still lack. This study were along the plots and transect lines made for mammal information to survey the vascular plants and vegetation types in relation to major environmental factors from Nan’an to T’a-fen. In addition, aerial photos or satellite images were used to the match terrain exercise to draw the distribution graph of Cyclobalanopsis glauca (Thunb.) Oerst. dominated in T’a-fen area. We expected to provide the basic data to understand the population dynamic, fauna distribution related to the plant communities. The study period was from March to December, 2009. The inventory results recorded 141 families, 487 genera, 883 species of vascular plant, including 39 rare species, 6 endangered, 13 vulnerable, 10 near threatened and 18 rare. 73 plots along 25 auto camera plots of wildlife were sampled. Tree and shrub layer data were combined to classify the vegetation types. Using two way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA), the results were showed 7 types, namely Callicarpa formosana - Alnus formosana type; Pinus taiwanensis - Cyclobalanopsis glauca type; Liquidambar formosana - Juglans cathayensis type; Schefflera octophylla - Cyclobalanopsis glauca type; Machilus zuihoensis var. mushaensis - Litsea acuminata type; Adinandra formosana - Cyclobalanopsis longinux type; Eurya leptophylla - Pinus morrisonicola type. Using canonical correspondence analysis (CCA), the result showed that alititude factor explain most variation of vegetation types. In addition, cover of shrub layer and herb layer, height and cover of tree layer, cover of litter layer, height and cover of moss layer, topography, rock were also significant relative to vegetation types and species distribution. In vegetation map of T’a-fen, 325 formal plots were set for quantatification of dominant species Cyclobalanopsis glauca. Combining with interior and outer characteristic of forest and orthoimage, Cyclobalanopsis glauca dominat vegetation and non-Cyclobalanopsis glauca dominat vegetation were distinguished. The results of digital data showed the area of Cyclobalanopsis glauca dominat vegetation was 225.42 ha, occupied about 45% of all T’a-fen mapping area.