Abstract: 3-Hydroxybenzoic acid（3-HBA） is a platform chemical with high practical application value, and plays an important role in microbial metabolism. Pseudomonas chlororaphis P3 is a high yield of phenazine-1-carboxamide mu tant strain with outstanding physiological and biochemical characteristics, which can be developed as a platform organism via metabolic engineering. In this research, the growth of P3 strain under different concentrations of3-HBA was evaluated, finding that P3 strain showed tolerance of growing in the 3-HBA over-accumulated environment. In addition, P3 strain could be cultured when applying 3-HBA as the sole carbon source, indicating that 3-HBA can be degraded. After sequence alignment, a gene had been identified to catalyze the degradation of 3-HBA. It was certificated that 3-HBA was degraded by gentisate pathway in P3 strain through exogenous expression and whole cell catalysis. This research revealed a degradation pathway of 3-HBA in P. chlororaphis P3, which laid a foundation for biodegradation of other aromatic compounds as well as exogenous synthesis and accumulation of 3-HBA in Pseudomonas.