The aim of this study was the identification and quantification of the main active compounds from different Romanian Usnea barbata L. extracts and evaluation of their antioxidant activity. The vegetal product Usneae lichen was harvested from Călimani Mountains, Suceava County, Romania, in March 2016. We prepared 10% extracts in: acetone, 96% ethanol and water. The quantitative analysis of the identified constituents was performed using an HPLC method. The antioxidant activity was evaluated by the scavenger DPPH (2,2-diphenyl-1-picrylhydrazyl) method. For this analysis, we prepared 20% extracts in: acetone, 96% ethanol and water. For each extract, we prepared two dilutions: 1:2 and 1:4. Our results showed that each extract contains usnic acid and polyphenols. The intensity of the antioxidant activity varied with the different solubility of polyphenols in each solvent.