The present study was conducted for quantitative analysis of plant diversity and community structure of tropical moist deciduous sal ((Shorea robusta Gaertn.) forest of Assam, northeast India. The study was carried out in Doboka reserve forest (longitude 92046′0′′- 92057′0′′ E and latitude 2606′0′′- 26013′0′′ N) located towards the South of Nagaon district of Assam. A total of 89 plant species (34 tree, 15 shrubs, 25 herbs and 15 climbers) belonging to 77 genera and 45 families were recorded. The Shorea robusta had highest IVI (125.3) followed by Dillenia pentagyna (27.24) and Careya arborea (23.12). The stand density and basal area of tree species recorded 422 individual ha-1 and 88.87 m2ha-1 respectively. Tree density in lower girth class i.e. 30-60 cm was found to be higher. Shannon-Wiener index of diversity ranges from 2.02 to 2.43. The study indicates that the tropical moist deciduous sal forest of Assam is a species diverse forest ecosystem.