Abstract: The paralytic shellfish poisoning (PSP) toxicity levels of shellfish collected from shellfish growing zones in Zhoushan areas of East China Sea and Shenzhen areas of South China Sea during January-November 2002 were determined with AOAC bioassay method. The results showed that the toxicity levels of shellfish from Zhoushan were very low,and few shellfish samples could be detected the PSPtoxicities.The same levels appeared in the shellfish from Shenzhen, but the percentage of shellfish samples contaminated PSP was up to 30%, and the scallop Chalmys nobilis was dominated in the contaminated shellfish species.Analyses on the toxic profiles of digest gland and edible tissue extraction of scallop from Shenzhen showed that a similar suite of toxins presented in the gland and edible tissues.The high potency neo STX and low potency GTX₅ had a high proportions, up to 60.8% and 11.4%,respectively in the tissue, and the high potency GTX ¹⁺² and GTX₅ were the dominant toxins, up to 38.9% and 20%,respectively in the gland. Most of the toxin were accumulated in ingested gland of scallop,and the toxic content in gland was about 8 folds more than that in the edible tissues.