Abstract: The investigation of marine fouling assemblages on concrete test panels in the northeast of Xinghua Bay was conducted from June 2017 to May 2018. A total of 94 species of fouling organisms belonging to 12 phyla were identified. The fouling organisms were mainly composed of coastal and warm water affinities and reflected distinct characteristics of subtropical embayments. The dominant species were Amphibalanus reticulates, its average density and biomass were 23 394 ind./m2 and 8 494.4 g/m2, respectively. Other major species included Cladophora sp., Amphiroa sp., Ectopleura crocea，Pennaria disticha，Lepidonotus tenuisetosus，Perna viridis，Magallana angulata，Balanus trigonus，Stenothoe gallensis，Caprella equilibra，Caprella scaura，Biflustra grandicella，Botryllus schlosseri，etc. The adhesive strength of the fouling organisms was highest in summer. The thickness, area, density and biomass colonized of the fouling were 30.5 mm, 100%, 25 175 ind./m2 and 8 783.6 g/m2, respectively. Followed by autumn, spring and winter,respectively. The adhesion strength in the second half of the year was significantly higher than that in the first half of the year. The vertical distribution of adhesion strength was not obvious. The main difference was that some algae adhered to the surface layer, while there was almost no algae distribution on the bottom layer.