From 95% alcohol extract of Ascidian Styela clava, collected from the shallow bay near Qingdao City, Shandong Province, six compounds, named, isovaleramide (1), thymine (2), thymidine (3), uracil (4), 2'-deoxyuridine (5) and ?-palmityl glycerin ether (6) were isolated,. Their structures were elucidated by various spectral analysis (IR, MS, ~1HNMR, ~(13)CNMR) and comparison of chemical and physical data with authentic samples reported in literatures. All of these compounds are first reported to be isolated from Ascidian Styela clava.