【Background】Macrobenthic community is an ecologically and functionally important component of a mangrove forest ecosystem. Macrobenthic communities, as well as their mangrove habitats are threatened by multiple human activity-mediated interacting stressors such as the establishment of invasive smooth cordgrass Spartina alterniflora. Many studies have investigated responses of benthic macrofauna to biological invasions by S.alterniflora. However, effects of removal of S.alterniflora on macrobenthic communities remain largely unknown. 【Method】The effects of mechanical removal of S.alterniflora on macrobenthic communities were examined in three regions (Shanjiao, Yong′an and Beijie) of the Shankou National Mangrove Nature Reserve, southern China. Benthic macrofauna in these three regions were collected quantitatively before and after the removal of S.alterniflora, and species composition, abundance and biomass were measured. 【Result】Macrobenthic communities changed significantly after S.alterniflora removal. Only one to three common species were detected before and after the removal of S.alterniflora in each region. Species richness increased in Yong′an and Beijie, but decreased in Shanjiao. Species abundance and biomass significantly decreased in all three regions surveyed. 【Conclusion and significance】Given that significant changes in macrobenthic communities may have substantial influence on food webs and ecological functions of the vulnerable mangrove ecosystems, attention must be paid on possible adverse effects caused by such dramatic changes when large-scale artificial removal of S.alterniflora is implemented in mangrove forests.