Abstract: Using litter bags,the authors studied the dynamics of dry weight, organic C,N, P of leaves of two species (Kandelia candel,Aegiceras corniculatum) in a mangrove community in Shenzhen during their decomposition in situ .Leaves of K.candel degraded more rapidly than those of A.corniculatum. For A.corniculatum ,it needed 35 days to lose half initial ash free dry weights (AFDW) of the leaves,while for K.candel ,only 12 days.Despite the difference in loss rate of litter bags with the two species,the dynamics of organic C,N, P of leaf detritus followed the same pattern.During decomposition,the N concentration of leaf detritus of both species rose up sharply,and then decreased gradually from the peak.The P level declined slightly,and then rose up slowly.The concentration of C remained fairly constant throughout the experiment.No significant difference in decomposition rates of the leaves of A.corniculatum was found when they degraded at different positions along tidal gradient within the mangrove ecosystem.