Supported by the technique of GIS and database and based on the survey data of two cruises in February (dry season) and August (wet season) of 1999 , this paper analyzed and evaluated comprehensively the status of water nutrient in Kaozhou Bay by using the method of data interpolation and grid weighting scheme. In the dry season , the water quality accorded with the first class of sea water standard without any organic pollution , while in the wet season it was in the second class with obvious organic pollution and eutrophication occurring in the northwestern waters and the estuary of Jilong River. The distribution trends of the primary productivity were similar in the two surveys , which were high in the mouth of the bay and low in the middle and northwestern waters. The distributions of the food organisms were irregular in both of the surveys. In the dry season they were evenly distributed with most of the waters belonging to the second or the third level , and the dense area was found in the northwestern waters , the mouth of the bay and the waters around Jilong River , while in the wet season , the food organism level varied distinctly with the dense area occurring in the middle waters of the bay and the coastal waters along Wangjingzhou village. Compared between the two surveys , the levels of primary productivity and food organisms in the wet season were higher than those in the dry season.