A novel method for the simultaneous determination of dissolved phenanthrene(Phe) and its intermediate metabolite 1-hydroxy-2-naphthoic acid(1H2NA) in aqueous solution was established by using derivative synchronous fluorescence spectroscopy.The linear dynamic ranges for the determination of Phe and 1H2NA were 4.0-1.0×103 μg/L and 4.0-1.2×103 μg/L,with the detection limits of 0.08 μg/L and 0.07 μg/L,and the spiked recoveries of 96.5%-105.3%and 99.2%-106.5%,respectively.And the relatively standard deviations were less than 1.0%.The established method was successfully applied in the determination of Phe and 1H2NA during biodegradation of dissolved Phe in lab,which showed that it has a potential in in situ determination of Phe and 1H2NA.