This is a multicenter, randomized, blinded, 3-arm Phase 3 study to evaluate the efficacy and safety of Fluzoparib alone or with Apatinib versus Placebo, as maintenance treatment, in patients with Stage III or IV ovarian cancer. Patients must have completed first-line platinum based regimen with Complete Response (CR) or Partial Response (PR). The study contains a Safety Lead-in Phase in which the safety and tolerability of Fluzoparib+Apatinib will be assessed prior to the Phase 3 portion of the study.

Inclusion Criteria:

• （phase 3）Histologically new diagnosed, advanced (FIGO Stage III or IV) high-grade serous or endometrioid ovarian cancer (including primary peritoneal and fallopian tube cancer)
• （phase 3）Complete response (CR) or partial response (PR) achieved with front-line platinum-based chemotherapy regimen as determined by investigator
• （phase 3）Ability to be randomized ≤8 weeks after last dose of platinum
• （Saftey Lead-in）Received 2~4 prior chemotherapy regimens. Platimun sensitive relapsed; Have at least one measurable disease as defined by RECIST v1.1.

Exclusion Criteria:

• Prior treatment with a poly (ADP-ribose) polymerase (PARP) inhibitor or Apatinib
• Patients who have received other study drug treatment within 4 weeks prior to the first administration(< 5 elimination half-lives of the study drug molecular targeted anti-cancer drugs).
• Patients with clinical symptoms of cancer ascites, pleural effusion, who need to drainage, or who have undergone ascites drainage within 2 months prior to the first administration.