Abstract: Chemo-resistance is one of the most importance reasons to explain the failure of chemotherapy. The over expression of DNA repairing gene in cancer cells lead to the chemoresistance. Poly（ADP-ribose） polymerase（PARP） is one of the DNA repairing enzymes by excising base which has been supposed to be one of the target of molecular targeting therapy. Recently plenty of PARP-related researches had been reported， which suggested that PARP inhibitors could sensitize chemotherapeutics as well as the antitumor effect alone. The text below will summarize the updating clinical researches of PARP inhibitors in recent 5 years.