Polycyclic aromatic hydrocarbons (PAHs) are the major sources of pollution that cause dangerous effects on human and other organisms. Biodegradation of PAHs in the contaminated area is an engaging remediation technique and its accommodation depends on the optimal condition for the PAH-degrading isolates. In the current study, four bacterial strains were isolated from polluted area with petrochemical compounds with  the ability for biodegradation of phenanthrene and pyrene. Only one strain has high biodegradation ratio of  phenanthrene and pyrene. The optimization process for biodegradation of phenanthrene and pyrene was executed and qualified under different conditions of shaking, static, pH, temperature, inoculum sizes, salt concentration, carbon and nitrogen sources. Phylogenetic tree based on 16S rDNA genetic analysis sequence indicates that this bacterial isolate was belonged to genus Pseudomonas and identified as Pseudomonas putida (H 18).  The optimal conditions for biodegradation were observed in media containing phenanthrene and pyrene as sole  carbon source, yeast extract  as nitrogen source, and 4% of inoculum size, at pH 8 and 35ºC under static condition for 8 days. The maximum biodegradation efficiency was reached to 92% of phenanthrene and pyrene and  was confirmed by using GS-mass spectroscopy.