The missing chemical Link (Phthalate) of bacterial metabolism pathway for 2-naphthoic acid has been identified to be existing. The genetic regulation mechanism of 2-NAT strain for 2-naphthoic acid metabolism is also investigated with plasmid curing, transposon Tn10 mutagenesis and mutation reversion experiments. It is discovered that 2-NAT strain carries at least one plasmid. The plasmid and the chromosomal DNA co-encode and control the bacterial metabolism pathway for 2-naphthoic acid.