Two compounds were isolated from the hard coral Pavona frondifera Lamarck collected from the South China Sea by chromatographied on gel colum and recrystallization. Their structures were determined by UV,IR,MS,1HNMR and 13CNMR data. It first reported about the chemical compounds of the hard coral Pavona frondifera Lamarck.

Five organic compounds were isolated from the marine sponge Axinyssa aplysi- noides collected from South China Sea. Their chemical structures were identified by UV, IR, NMR, and MS as 4-hydroxybenzaldehyde (I); (22E)-24,26,26-trimethylcholesta-6,22,25 (30)-trien-3?-ol(Ⅱ); 3- (17Z-tetracose-nyloxy)-1, 2-propanediol (Ⅲ); 24-isobutylcholesta-3, 25(31)-dien-3?－ol(Ⅳ); Uracil (V). It's the first report about the marine sponge Axinyssa aplysinoides from South China Sea.

Eight active compounds were isolated from Bugula neritina Linnaeus collected off Dapen Bay in Guandong province, guided by P 388 bioassay system by a combination of successive chromatographies and preparative HPLC. By intensive analysis of the data of high resolution 2D NMR spectrum and ESI MS, their structures were elucidated as known bryostatins--bryostatin 4, 5, 6, 8, 10, 11, 16 and 18, among which bryostatin 8 and 16 were for the first time obtained from this animal in South China Sea and they showed significant antineoplastic activities in vitro.

Five compounds were isolated from the ethyl acetate extract of the marine sponge Cin-achyrella australiansis collected from the South China Sea. Their structures were identified by IR,1 H-NMR,13C-NMR,MS as the follows : 24-ethyl-cholest-4-en-3-one(Ⅰ), cholesterol (Ⅱ), benzene- ac-etamide(Ⅲ), p-hydroxyphenylacetamide(Ⅳ), indole-3-acetamide(Ⅴ).