The tempo-spatial variation of macrobenthic communities was studied on a tidal flat of Wenzhou Bay, China from November 2003 to August 2004. We collected 38 macrobenthic species belonging to 23 families, 8 classes and 7 phyla, most of which were arthropods and molluscs. Species richness, density and biodiversity significantly differed between tidal zones, seasons and the interaction between them. The tempo-spatial variations of the macrobenthic communities were also shown in cluster and ordination analysis. The middle tidal zone during autumn tends to have the highest values of the community descriptors. Thus, tidal zone and seasons have significant roles in structuring these communities.