For useful basic data in new ascidian processed products, this study investigated and compared the biological activities of two ascidians, Styela clava and Styela plicata, in two conditions with fresh one and cooking one at $100^{circ}C$ for 10 min. By fresh state, Styela clava (8.46 mg/ml) had higher activity than Styela plicata (13.67 mg/ml) in the antioxidative assay ($EDA_{50}$), whereas Styela plicata (10.54 mg/ml) had higher than Styela clava (12.05 mg/ml) after cooking. Particularly the antioxidative activity of Styela plicata increased 1.3 times after cooking. Fresh Styela clava had antimicrobial activity against Bacillus subtilis, B. cereus, E. coli, whereas the activity appeared against E. coli only after cooking. However, antimicrobial activity in Styela plicata appeared against 4 gram positive bacteria (B. subtilis, B. cereus, S. aureus and L. monocytogenes) and E. coli, regardless of concentration level (1,000-1,500 ppm) and with/without cooking. ACE inhibitory activity was not observed in the samples. By cooking, the level of fibrinolytic activity increased to 1.79 from 1.24 plasmin unit/ml in Styela plicata, whereas the level decreased to 1.55 from 1.62 in 5tyela clava.