Degradation of polycyclic aromatic hydrocarbon were studied by using the bacteria pseudomonas sp. isolated from soil contaminate with oil. The yield of microbial cells reaches a maximum at pH value of 7 for five different phenanetherene concentration media (5-25) mg/ml. At temperature of 32oC, the growth was activated established metabolism within five days. Higher biomass concentration obtained with time of 22.5 min for initial substrate concentrations of 25 mg / ml. The change of cell growth and substrate concentration with time is directly proportional to time while substrate concentration decreases exponentially with time. These results analytically confirmed that the bacteria undergoes Monod's Kinetics. The order of degrading phenanthrene is obvious when a limiting substrate ( 5 or 10 mg/ml ) is been used , the degradation processes are rather sluggish than those observed in ( 20 or 25 mg/ml ). First order curve fitting was determined that the statistical software Statistica was used for estimating Monod’s kinetics constants.