The purposes this study of plant community at Ton Ao Yon waterfall, Phuket Island. Distance is 1000 m^2. Place the converted sample size 10 x10 m. Both beside a stream Ton Ao Yon waterfall. Each side 5 conversion (including 10 conversions). Analysis of plant species such as Density (D), Dominance (Do) and Frequency (F) to determine Importance Value Index (IVI) and Analysis of Biological diversity. It can be summarized that plant community in the lower montane rainforest composed of 30 species and 15 families. It concluded that the highest ImportanceValue Index (IVI) in lower montane rainforest were Morinda elliptica Ridl. (35.97) Spondias pinnata Kurz. (31.30) Microcos tomentosa Sm. (22.35) Pterocymbium tinctorium (Blanco) Merr. (19.49) Garcinia merguensis Wight. (17.52) respectively. The area around Ton Ao Yon waterfall were richness indices (R) 7.30, diversity indices (H’) 3.24 and evenness index (E) 0.95. The results of this study can be used as a basis to learn important source of natural and in dealing with the local community to be useful in the area of sustainable.