The Patungkuan Lat e r a l Tr a il i s l o c a t e d a t the heart of Yu s h a n N a t i o n a l P a r k . T h i s 11 5 - k i l o m e t e r o l d p a s s a g e s t r e t c h i n g o v e r N a n t o u H s i e n a n d H u a l i e n H s i e n , w i t h elevations from Tungpu, 1000m, ascending to Tashuiku, 3200 m, and descending to Cholu, 300m. Due to the var i e ty of habitats within Yushan National Park, it products a very abundant flora, the area can be distinguished to some forest zones, including the broad-leaved fores t zone, coniferous forest zone, mixed coniferous and broad-leaved forest zone, and subalpine scrub zone, etc… Seventy-seven sample plots were sampled and applies Multiple plot method to investigate the composition and structure of vegetation along the passage, applies Matrix Cluster Analysis(MCA) and Ordination method to analyze the variant characte r i s t ics of vegetation, and makes correlation test with environmental factors in order to realize the differentiation of every vegetation type along the environmental gradient. 363 species of vascular plants were investigated and 16 vege t a t i o n t y p e s a r e c l a s s i f i c a t o n a s fo l l o w s : ( A) Ma c h i l u s zui h oens i s-Li t s e a a cumi n a t a t y pe , ( B ) I t e a par v i f l o r a va r. p a r v i fl ora-Carpinus kawakami i type, (C) Glochidion rubrum -Cinnamomum insular imontanum type, (D) Idesia pol y c arpa - C a l l i c a r p a f o r m o s a n a t y p e , ( E ) N e o l i t s e a a c u m i n a t i s s ima - C y c l o b a l a n o p s i s p a c h y l o m a t y p e , ( F ) J u l g l a n s c a t h a y e n s i s -Machilus zuihoensis type, (G) Phoebe formosana-Machilus kusanoi type, (H) Cyclobalanopsis glauca –Quercus variabilis t y p e , ( I ) A l n u s j a p o n i c a t y p e , ( J ) C y c l o b a l a n o p s i s stenophylloides –Chamaecyparis formosensis type, (K) Pinus taiwanensis –Rhododendron rubropilosum type, (L) Quercus s p i n o s a - S t r a n v a e s i a n i i t a k a y a m e n s i s t y p e , ( M ) Ts u g a chinensis-Schefflera taiwaniana type, (N) Cinnamomum insula rimontanum –Elaeagnus glabra type, (O) Adinandra lasiostyla -Elaeocarpus japonicus type, (P) Abies kawakamii –Berberis mor r i s o n e n s i s t y p e . I t shows that the vegetations within the study area can be divided into three groups by int e r s p e c i f i c a s s o c i a t i o n . T h e results by the analysis of population structure and species div e r s i t y s h o w t h a t t h e P i n u s t a iwa n e n s i s – R h o d o d e n d r o n rubropilosum type and Alnus japonica type are situated in the frontier stage of succession, however, others are situated in the mor e s t a b l e s t a g e . In this paper, in addition to taking vegetation analysis, assessment and selection of rare and endangered plant s within t h e a r e a a n d t h e s u g g e s t i o n o f a p p r o p r i a t e c o n s e r v a t i o n managements are taken, in order to offer the references of conservation program of Yus h a n N a t i o n a l P a r k .