Pollution condition of organic matter and nutrient salts and nutri-tion type were analysed to the investigation of Dingzi Bay waters during shrimpculture season in 1987. The results showed that the waste water discharged fromlarge area shrimp ponds could result in eutrophication in the bay and thus causeserious pollution of organic matter and nutrient salts. Pollution degree and nutri-tion type evidently varied in season. IP was a restrictive factor that limited theincrease of primary production in the waters. The possibility of occurance of redtide in Dingzi bay waters was also discussed.