The widespread use of broad-spectrum antibiotics has resulted in antibiotic resistance for many human bacterial infections, making multi-drug resistance a significant challenge in the treatment of infectious diseases. The antibacterial impact of phenolic plant extracts has been studied in new and different ways. The phenolic extract of Thymus vulgaris, Artemisia annua and pure thymol were used to study bacterial biofilm formation. In addition, the experiments were carried out to determine the lowest inhibitory concentrations in order to evaluate the antibacterial impact (MICs) against 20 isolations of Pseudomonas species. In this report, the plant extract was analyzed by HPLC techniques to determine the Thymol value. Although the Thymus vulgaris and Artemisia annua phenolic plant extracts and pure thymol concentrations (50, 25, 12.5, 6.25, 3.125, 1.250 and 0.006 mg/ml) (W/V)) were used through antibiotic and biofilm inhibition assay. The best results of MICs of T. vulgaris, A. annua extract and pure Thymol against bacteria isolates were 5.000 mg/ml, 1.250 mg/ml and 0.006 mg/ml, respectively. Stimulatory, the effect of T. vulgaris, A. annua extract and pure Thymol on biofilm formation were gave 10 mg/ml, 5mg/ml and 0.006 mg/ml respectively.