A survey reveals that the community of fouling organisms in the seawater testing pool of a marine environmental test station set at Sanya Bay on Hainan Island showed features of fewer species, lower density and smaller size of individual, which is quite different from those of the of natural seawaters at the vicinity and even other tropical sea areas. By investigating the ecological distribution of the species of fouling organisms in the test pool, the pool structure and the water quality, as well as the relevant meteorological events, it is found that the existence of concrete-made seawater test pool with designed structure can significantly change the flow state of the original sea area and even the ecological environment conditions of the natural sea area at the vicinity, as a consequence, the concentrations of α-chlorophyll and nitrate within the pool were only 1/5-1/6 of that in the natural seawaters at Sanya Bay. In addition, high intensity scour may emerge in the testing pool during storm surge, strong heat effect may generate on the pool wall by low tide exposure, and there even exists extreme natural disasters such as heavy rain lasting more than 5 h. As a result of all of the above factors, there are few species of the community of fouling organisms may form in the tidal zone area of the cement wall of the pool. The dominant species are the Ostrea mordax in the pool. Besides, on the surface of non-toxic test plates that have been immersed for more than five years, only rare tube-dwelling polychaetes and Xiamen oysters attach. It is also found that the corrosion rate of non-passivable ferrous metal materials in the pool was much faster than that in natural tropical marine areas at Sanya Bay. This study illustrated that man-made facilities set in natural sea area could greatly affect the composition and structure of fouling organisms community, and thus affect the degree of accuracy of the detection- and evaluation-results of the antifouling performance and corrosion process of materials.