The characteristics, distributions and sources of parent polycyclic aromatic hydrocarbons (PAHs) and alkyl-PAHs (A-PAHs) as well as their ecological risk were explored in six mangrove wetlands across the Taiwan Strait, China. A-PAHs fingerprinting information, combined with PAHs diagnostic ratios and a positive matrix factorization model, were used to identify the sources of PAHs in the mangrove wetland surface sediment samples. The results showed that the total concentration of the 36 PAHs in the sediment samples varied from 186.2-2469.2 ng⸱g^-1. Furthermore, the total concentration of PAHs would be underestimated about 37.1%-80.6% when only the concentrations of 16 priority PAHs were examined in the sediment samples. Coal combustion (32.7%) and petroleum combustion (24.6%) were identified as important contributing sources in the Yunxiao, Fugong, and Quanzhou mangrove wetlands, whereas the main source was mainly petroleum combustion (49.1%) in the Guandu, Zhuwei and Waziwei mangrove wetlands. In addition, the guidelines for assessing the ecological risk of individual A-PAHs need to be developed due to lack of criteria for most individual A-PAHs.