A kind of three-dimensional (3D) surface-enhanced Raman scattering (SERS) substrate with a high sensitivity is developed for the rapid detection of the trace polycyclic aromatic hydrocarbons (PAHs) in water. The 3D SERS substrates with a high sensitivity are formed by the combination of the GMA-EDMA porous material with the Au nanoparticles with optimal parameters. The signal intensity of this 3D SERS substrate has an enhancement by one order of magnitude compared with that of only parameter-optimized Au colloid solution SERS substrate, and by about two to three orders of magnitude compared with that of natural Au solution substrate. Moreover, there exists a good repeatability. The relative standard deviation (RSD) of detection is 4.78%-9.27% within substrates and 2.05% between substrates. The SERS spectra of these three kinds of representative PAHs, phenanthrene, pyrene and benzo(k) fluoranthene are detected by the usage of this 3D SERS substrate, and their limits of detection are 9.0×10 -10、 2.3×10 -10 and 5.9×1 0-10mol·L -1, respectively. The results show that this detection method possesses a simple operation, a good repeatability, and a high sensitivity, which can be used for the trace detection of PAHs in water.