The present study was carried out for quantitative analysis of plant diversity, population structure and regeneration status of tropical moist mixed deciduous forest of Assam, northeast India. The study was carried out in Lumding reserve forest (longitude 9300'0''- 93015'0'' E and latitude 25045'0''- 25052'0' N) located towards the South of Nagaon district of Assam. A total of 145 plant species (90 tree, 18 shrubs, 26 herbs, 9 climbers and 2 lianas) belonging to 112 genera and 59 families were recorded. Shannon-Wiener diversity index (2.18 to 3.74) and Simpson's index (0.03 to 0.15) were within the range reported for different Indian tropical forests and indicate that Lumding reserve forest is a species diverse forest. A few dominant tree species like Holarrhena antidysenterica, Diospyros embryopteris, Albizzia lebbek, Mallotus philippensis, Litchi longana depending on size-class distribution showed reverse J-shaped population curve and Trewia nudiflora showed J- shaped curve. Most of the tree species (44%) showed 'fair regeneration'.