Abstract: In the laboratory, the study on the absorption of PAHs (including acenaphthene, phenanthrene, chrysene) in the seawater by the leaf litter of Sonneratia apetala, Kandelia candel and Bruguiera gymnorrhiza was conducted under different decomposed states of the leaf litter.The result showed that the total absorbing amount of PAHs by the leaf litter of S.apetala, K.candel and B.gymnorrhiza varied significantly(P < 0.05) under the same PAHs concentration (90, 900 or 9000 μg/L), and the absorption rate by the leaf litter of the three mangrove species was significantly different.When the concentration of PAHs in seawater is at 90 and 900 μg/L, the absorption rates of PAHs by the brown leaf litter of S.apetala were the highest in the leaf litter of the tree mangrove species, which were 32.6% and 35.1%, respectively.The absorption of PAHs by the leaf litter of the three mangrove species varied as follows:the absorption rate of brown and black leaf litter of K.candel rose with the increase of PAHs concentration; the absorption rate of brown and black leaf litter of B.gymnorrhiza first increased (from 90 to 900 μg/L) and then decreased (from 900 to 9000 μg/L) with the increase of PAHs concentration; the absorption rate of brown leaf litter of S.apetala grew with the increase of PAHs concentration while black leaf litter rose at first and went down later with the continuous increase of PAHs concentration.Laws of absorption rate of the leaf litter of three mangrove species to single PAHs were also discrepant.For the same tree species and the equal decomposed state, the leaf litter absorption rate differed respectively from acenaphthene, to phenanthrene and to chrysene.