To establish a fast analytical method for simultaneous identification of polycyclic aromatic hydrocarbons (PAHs) in Water, a novel method of constant-wavelength synchronous fluorescence was proposed to the simultaneous determination of different PAHs in a mixture of 6 components. Combing the technique with a system that allowed a crude sample separation based on optimum conditions, detection conditions provided increased selectivity and sample information, and 6 PAHs could be identified and quantified by the corresponding synchronous spectra. The linear response of this method was in the range of 0~1000ng/mL (r≥0.9965), the relative standard deviations (RSD) were in the range of 0.24%~1.48% (n = 6). The detection limits were in the range of 0.028-3.45ng/mL. By using this method, real samples were determined directly and good results were obtained with the recoveries of 66.3%-103.9%, 73.9%-100.3% for spiked river samples