This study was conducted during 2018-19 to evaluate the floristic composition and ecological characteristics of vegetation of Pashat valley, Bajaur. Floristic list of the valley contains 385 species distributed in 291 genera and 102 families. The dicotyledons having 83 families with 311 species and monocotyledons with 12 families con-tains 61 species. Pteridophytes having 05 families with 11 species and gymnosperm with a single family of two species. The leading family was Asteraceae with 42 species (10.90%) followed by Poaceae with 39 species (10.10%), Papilionaceae (Fabaceae) with 24 species (6.23%), Lamiaceae with 20 species (5. 19%) and Rosaceae with 15 species (3.90%). Therophytes 180 species (46.80%), hemicryptophytes 53 species (13.80%), nanophanerophytes 51 species (13.20%) and geophytes 35 species (9.09%) were the dominant life form groups. Leaf size class was dominated by microphylls (138 species, 35.84%) followed by nanophylls (124 species, 32.21%) and mesophylls (89 species, 23.12%). Habit wise the vegetation was mostly herbs (289 species) followed by shrubs (54 species), trees (38 species) and lianas (4 species). According to flowering phenology, most plants (62.30%) bloomed in spring followed by in summer (34%), in autumn (1.82%), in the whole year (1.30%) and in winter (0.52%). Based on chorological affinities, most of the species were bioregional in distribution (170 spe-cies, 44.15%) followed by mono-regional (157 species, 40.78%), pluri-regional (43 species, 11.17%) and cosmo-politan (15 species, 3.89%). The ecological characteristics like life form and leaf size spectra of the vegetation have a strong correlation with the prevailing environmental conditions such as altitude, slope, precipitation and temperature.(c) 2021 Ecological Society of China. Published by Elsevier B.V. All rights reserved.