Extracts of 21 marine invertebrates belonging to Coelenterata, Mollusca, Annelida, Bryozoa,Echiura, Arthropoda, Echinodermata and Urochordata were screened for the studies on their antitumor and immune regulation activities. Antitumor activity was determined by MTT method and immune regulation activity was studied using T- and B-lymphocytes in mice spleen in vitro. It was found that the n-butanol part of Asterina pectinifera, the acetic ether part of Tubuaria marina, 95% ethanol extract of Acanthochiton rubrolineatus have a high inhibition rate of 96.7%, 63.9% and 50.5% respectively on tumor cell line HL-60 at the concentration of 0.063 mg/ml. The inhibition rate of the acetic ether part of Tubuaria marina on the tumor cell line A-549 is 65.4 % at concentration of 0.063 mg/mL. The 95% ethanol extract of Meretrix meretrix has so outstanding promoting effect on T-lymphocyfes that their multiplication increases 25% when the sample concentration is only 1 μg/ml. On B-lymphocytes, the 95% extract of Rapana venosa, at concentration of 100μg/ml, has a promotion percentage of 60%. On the other hand, under the condition of no cytotoxic effect, the 95% ethanol extracts of Acanthochiton rubrolineatus and Cellana toreum can reach 92% inhibition rate on T lymphocyte at concentration of 100 μg/ml, while the inhibition rate on B lymphocyte of the 95% extract of Acanthochiton rubrolineatus reaches 92% at the same concentration.