Disclosed are an aza-phenalene-3-ketone derivative, a preparation method thereof and its application as a PARP inhibitor. The aza-phenalene-3-ketone derivative has the following structure:wherein R is hydrogen, methyl, ethyl, isopropyl, benzyl or 3-methyl-3-butenyl. The aza-phenalene-3-ketone derivative has very high activity for inhibiting PARP, thereby providing a good basis for new drug research of developing a nitrogen-doped phenalene-3-ketone compound as PARP inhibitor to treat cancer.
