［Objective］ The pollution characteristics and ecological risks of polycyclic aromatic hydrocarbons （PAHs） in small coastal urban watersheds were explored， to provide a scientific basis for pollution source tracing and ecological risk management in such regions. ［Methods］ Houxi River watershed in Xiamen City was selected as the study area. Surface sediment samples （0—5 cm） were systematically collected from 18 sites and quantitatively analyzed for 16 PAHs using gas chromatography-mass spectrometry （GC-MS）. ［Results］ The results showed that the total content of 16 PAHs in the surface sediments of Houxi River watershed in Xiamen ranged from 115.02 to 807.27 ng/g， with an average of 371.33 ng/g. Among them， 4-ring and 5-ring PAHs had the largest proportions， both exceeding 25%. 2-ring PAHs had the smallest proportion， less than 4%. 3-ring and 6-ring PAHs were in the middle， around 20%. The spatial distribution showed a clear gradient among the upper， middle， and lower reaches： the upstream （A） had the lowest concentration （86.23—153.61 ng/g）， the middle reaches （B） were intermediate （298.23—456.71 ng/g）， and the downstream （C） had the highest concentration （435.24—656.11 ng/g）， indicating that the PAH pollution increased with the intensity of human activities. Based on the Sediment Quality Guidelines （SQGs）， the ecological risk assessment showed that most sampling sites fell between the lowest-level rare effect level （REL） and the second-lowest-level threshold effect level （TEL）， and a few sampling sites reached the medium-level occasional effect level （OEL）. None of the sampling sites reached the higher-level probable effect level （PEL） and the highest-level frequent effect level （FEL）. ［Conclusion］ The overall ecological risk of PAHs in the surface sediments of Houxi River watershed in Xiamen City is within a controllable range. However， variations in ecological risks across different sampling sites and PAH compounds should be given attention by relevant authorities.