Beech forests of northern Iran in the Hyrcanian ecosystem are considered as the richest and most valuable forests in the northern hemisphere. The present study was carried out in the part of the district No 3, Nav, Asalem (3770 ha) in the west of Guilan Province. In order to identify the flora, the Chorology, life forms and growth forms, herbaceous understory plants within the beech forests were studied. Totally, 109 plant species belonging to 75 genera and 41 families were identified in the Asalem beech forests, Which in the species of Vicia abbreviata spreng. of the Papilionaceae family and Hieracium vulgatum spreng. of the Asteraceae family have been reported for the first time in Guilan province. Families of Dryopteridaceae, Lamiaceae, Orchidaceae, Poaceae and Papilionaceae comprised a total of 35 species (32.1%). The most important life forms belonged to geophytes (48.6%) and hemicryptophytes (40.3%) in the this region. Chorological study also showed the dominance of the Hyrcanian phytogeographical region. In terms of growth forms, frequency of forbs, grasses and ferns was 77%, 12% and 11%, respectively. The presence of 109 herbaceous plants in understory showed the higher herbaceous species richness in this forest which is due to Asalem beech forests location that lies in suitable geographical position and site under the impact of Hyrcanian climate. The higher Europe-Siberian vegetation confirms this issue.