The macrobenthos are the primary consumers in the mangrove ecosystem and play an important role on nutrient transformation and energy transportation. By conducting the indoor feeding experiment, the feeding characteristics of two common macrobenthos in the Southern China coastal region mangroves, Sesarma dehaani and S. bidens, to the leaf litter of the exotic mangrove species Sonneratia apetala, and two native species, Kandelia obovata and Aegiceras corniculatum were studied. The results showed that the leaf litter of Kandelia obovata had the greatest changes in Tannin content and C/N value during the leaching process, which decreased (45.85±7.74) g?kg-1 and 11.24%. Meanwhile, the decreasing rates of Tannin content and C/N value are (45.15±11.14) g?kg-1 and 2.43%, (18.75±15.15) g?kg-1 and -1.36% respectively for Sonneratia apetala and Aegiceras corniculatum. With the decrease of Tannin content and C/N value, the two Sesarmid crabs′ predation of leaves presented a slightly rising trend accordingly, which rised from 3.097 g to 10.079 g and 2.480 g to 8.723 g for Sesarma dehaani and S. bidens, respectively. In addition, there was no significant difference with the food preference between the two crabs (P<0.05), but there was significant difference between the three mangrove species. Both of the crabs were significantly prefer to Sonneratia apetala and Kandel obovata rather than Aegiceras corniculatum due to the high Tannin content and low nutritive value in the litter′s leaves (P<0.01). The results proved that introducing the exotic species Sonneratia. apetala at a large scale would incur the potential impact on the food chain structure in the Southern China coastal regeion mangroves, and also provided the reference for mangrove ecological restoration and reasonable afforestation.