The present invention relates to a novel tricyclic derivative with efficient inhibitory activity against poly(ADP-ribose)polymerases (PARP) or pharmaceutically acceptable salts thereof, a preparation method thereof, and a pharmaceutical composition containing the same. The tricyclic derivative of the invention is useful for the prevention or treatment of diseases caused by excess PARP activity, especially neuropathic pain, neurodegenerative diseases, cardiovascular diseases, diabetic nephropathy, inflammatory diseases, osteoporosis, and cancer, by inhibiting the activity of poly(ADP-ribose)polymerases.
