Pyrazolofluostatins A-C (1-3), three new benzo[a]fluorenes with an unprecedented carbon skeleton, were obtained from the South China Sea-derived Micromonospora rosaria SCSIO N160. Their structures were elucidated by extensive spectroscopic analyses. The structure of pyrazolofluostatin A (1) was confirmed by X-ray crystallographic analysis. Notably, 1-3 possessed a benzo[cd]indeno[2,1-f]indazol skeleton with a pyrazole-fused 6/5/6/6/5 pentacyclic ring system. Pyrazolofluostatin A (1) showed moderate antioxidation activity (EC50 48.6 μM).