The metabolic pathway of phenanthrene-degrading strain Agrobacterium sp. Phx1 was investigated. Phx1 almost was able to transform 100μg/mL of phenanthrene completely in 1 day in broth media of beef extract-peptone (BP), Luria-Bertani (LB) and mineral salts media (MS), and LB and BP could promote the growth and degradation efficiency of Phx1. The GC-MS was employed to analyze the metabolites of the 1st, 3rd, 7th days of phenanthrene degradation in MS. As a result, the 1-Hydroxy-2-naphthoic acid (1H2N) and 1-naphthol (NOL) were detected in the metabolites of the 1st day. Only NOL was observed on the 3rd day and it disappeared on the 7th day. The accumulated NOL did not pertain to the defined pathway of phenanthrene degradation by bacteria. The further HPLC study confirmed the finding in GC-MS analysis and found the production of catechol (CAT) from ophthalic acid (OPA) in the phenanthrene metabolizing, which has never been reported in the defined degrading pathways. This production was also evidenced by the production of CAT using OPA as substrate. All of our results showed that the Agrobacterium sp. Phx1 had a novel phenanthrene-degrading pathway. Phx1 was able to transform 100 μg / mL of phenanthrene completely in 1 day in broth media of beef extract-peptone (BP), Luria-Bertani (LB) and mineral salts media (MS), and LB and BP could promote the growth and degradation efficiency of Phx1. The GC-MS was employed to analyze the metabolites of the 1st, 3rd, 7th days of phenanthrene degradation in MS. As a result, the 1 -Hydroxy-2-naphthoic acid (1H2N) and 1-naphthol (NOL) were detected in the metabolites of the 1st day. Only NOL was observed on the 3rd day and it disappeared on the 7th day. The Accumulated NOL did not pertain to the further pathway of phenanthrene degradation by bacteria. The further HPLC study confirmed the finding in GC-MS analysis and found the production of catechol (CAT) from ophthalic acid (OPA) in the phenanthrene metabolizing, which has never been reported in the defined degrading pathways. This production was also evidenced by the production of CAT using OPA as substrate. All of our results showed that the Agrobacterium sp. Phx1 had a novel phenanthrene-degrading pathway.