43 main fish species were collected and 940 stomach contents be got altogether in the adjacent waters of Nansha Islands and reefs. Based on the food habits of those fish analyzed and their food organism ecological groups as well as their digestive organ characteristic, as a general, they may be divided into such five kinds of feeding habits as plankton feeding habit, benthos feeding habit, swimming animals feeding habit, both plankton and benthos feeding habit, both benthos and swimming animals feeding habits. Based on the relationship among each nutrient class in food web, they may primarily be divided into four nutrient classes, i.e., primary producer (marine plants), phytophage animals and miscellaneous feeding habit animals, low and middle carnivorous animals, high class carnivorous animals. And according to the nutrient class divided, 43 species may be devided into low class carnivorous fish, middle class carnivorous and high class carnivorous fish with ratio being 28:10:5 in the adjacent water area of Nansha Islands and reefs. Gymnocranius griseus (Tenminck et Schlegelel ) was the decisive fishing target by trammel net in the adjacent water area of Nansha Islands and reefs. From the view point of food web, it should be strengthened for fishing the enemy fish and competitor of G.griseus, in order to remove the enemies of low class carnivorous commercial fish, thus the biomass of G.griseus may increase.