Ulin (Eusideroxylon zwageri) is a unique tree species in Kalimantan because of its most durable wood and only grow in mixed lowland dipterocarp forest habitat. The aim of this research is to analysis of floristic composition, diversity and structure of mixed ulin Forest of Local community Forest in Panarung village, subdistrict of Bentian Besar, West Kutai Regency, East Kalimantan. This forest as small remnant of lowland mixed tropical forest after its surrounding forest was converted to palm oil plantation. The Result showed the species richness were 196 species, which were consisted of 147 tree species, 16 species of lianas, 13 species of herbs, 12 species of shrubs, 5 species of ferns, 2 species of rattan dan 1 species of palm. Tree stage consisted of 97 species, 70 genera and 36 families. Species diversity (H’), showed that tree dan sapling stages were high where 3.82 for tree and 3.92 for sapling stages, while seedling in moderately, with H’= 2.49. Evenness (E) in tree stage was 0,83, while sapling and seedling were 0.87 and 0.55 respectively. This forest contained 28 species of endemic, 2 species of critically endangered (CR), 2 species endangered (EN) and 10 species in vulnerable (Vu).