This study examined the density, species composition, basal area (BA) and importance value index (IVI) of trees while, in the Sariska Tiger Reserve (STR) shrubs were examined for density and frequency. Two areas were selected for investigation: the core and the buffer area. The total tree density was 113 species/ha in the core area and 99 species/ha in the buffer area. Furthermore, the BA was 68.40 m²/ha in the core area and 44.47 m²/ha in the buffer area. Anogeissus pendula Edgew. was identified as the prominent species of tree in both areas, displaying the highest density, frequency, basal area and IVI. The total shrub density in the core area was 2,255 compared to 1,440 species/ha in the buffer area. The most dominant shrub species in both areas was Justicia adhatoda, which also exhibited the highest density and frequency. In the tree density, BA significant effect (p<0.05) was found and shrub density among core and buffer area, respectively. The diversity indices indicated higher diversity of trees in the core area with increased Shannon index i.e. 2.11 compared to (1.58) buffer values. In contrast, the Simpson (0.77), the Marglef index (6.06), and the Pielou index (0.74) were higher for the tree in the core than the buffer (0.75), (4.1), and (0.62) respectively. However, in the buffer area the shrub species had a higher Shannon index (2.46), Simpson (0.93) and Pielou index (0.82) than core (2.39), (0.92), (0.73) respectively. Additionally, core shrub species had a higher Marglef index (9.02) than core shrubs (7.22). The potential for this study to advance our understanding of the phytodiversity and composition of tree species in the STR makes it significant.