The coral reef ecosystem has high biomass and gross primary productivity, locates in tropical areas noted for very low dissolved nutrient concentrations. The reefs are truly “an oasis in a desert ocean”. The high productivity supporting the coral reef ecosystem is a “reef nutrient paradox”. Many researchers regarded the apparently contradictory aspects of and directed towards resolution of the “reef nutrient paradox”. About one quarter of the most recent research reports on “coral reef” concerns problems broadly termed the nutrient paradox. The main conclusion was that the coral reef ecosystems have low net productivity despite their high gross productivity, and are typically autotrophic communities. The main viewpoints were as follows: 1. The temperature of coastal upwelling water can drop below the lethal limit of algalcoral ecosystems; nutrient-rich upwelling water should produce a bloom of planktonic and benthic algae which should lead to a decrease in the input of light to the zooxanthellae-coral endosymbiotic system and eventually to eutrophication and coral polyp suffocation: increased destruction of reef frameworks by bioeroders whose abundance is directly related to the increase benthic algal biomass. 2. In oligotrophic regions, endo-upwelling can provide new nutrients to sustain the net primary production by zooxanthellae-coral symbiosis; Such primary production in turn supports coral skeletogenesis, microbial production and internal recycling of detrital organic matter injected into reef matrix by wave energy; The excess production and recycling of inorganic nutrients and organic carbon (chiefly zooxanthellae, mucus and dissolved organic mater) are exported to the adjacent ocean. Excess zooxanthellae purged in enormous numbers by the coral polyps may be consumed by zooplankton and benthos, the first links of the reef food chain. This food chain centered around a toll and barriers reef crests may explain the high biomass and secondary production observed in these oceanic oases. A permanent endo-up-welling can bring new nutrients to the surficial autotrophs, supporting the long-term growth and exportation of the ecosystem. 3. In the coral reef lagoons, the nutrient recycling is very rapid, water movement can transport nutrients into the lagoons and accelerate the nutrient assimilation of organisms. Based on a study of the Nansha coral reef ecosystem, South China Sea, this paper presents a new viewpoint -- “simulated drift-net theory”, which the reef nutrient paradox may be explained satisfactorily. The new viewpoint includes two parts: a. The main reason for the high gross productivity in the coral reef ecosystem is that the fixed tropical organisms there can enrich with a great amount nutrients in the oligotrophic water coming out from the reef. Because the coral reef organisms are relatively fixed and cannot drift with the moving water, they can adsorb much nutrients and become "nutrient enricher" of nutrient-poor waters. As a metaphorical meaning, the fixed organisms like a drift-net. Although fish is relatively little, they come into drift-net and are caught. The result is that fish is very much in drift-net. The "Simulated drift-net theory” is summarized in one sentence: The reason for the high gross productivity supporting the coral reef ecosystem is that the special biochemical reactor made up of relatively fixed tropical organisms enriches with a great amount nutrients the oligotrophic water coming out of the reef. b. The nutrient recycling in coral reef ecosystem is very rapid (about 5 to 25 times a year).