The objective of this study was to evaluate the real-world application, efficacy, and safety data of olaparib for maintenance therapy and active treatment in patients with ovarian cancer in China. Patients with ovarian cancer from 17 institutions in China treated with olaparib as maintenance or active therapy from January 2018 to March 2020 were included in this study. The medical records were reviewed, and follow-up information was collected for analysis of the patients' clinicopathologic characteristics as well as the effectiveness and safety of olaparib. A total of 251 patients receiving olaparib were included, with 84 as maintenance therapy after first-line chemotherapy (FL-M), 97 as maintenance therapy after platinum-sensitive recurrence (PSR-M), and 70 as active treatment (AT). The probability of progression-free survival (PFS) at 12 months was 87.6% in the FL-M group and 63.8% in the PSR-M group. According to the multivariate analysis, complete response (CR) to chemotherapy for the PSR-M patients was the only factor affecting the PFS (HR = 0.414, P = 0.014), and platinum sensitivity was the only factor affecting PFS improvement in the AT group (HR = 0.317, P = 0.009). In the AT group, the objective response rate was 37.1%, the CR rate was 7.1%, and 30% of the patients had stable disease. Eight (3.2%) patients discontinued olaparib due to toxicity. Anemia was the most common adverse event. In conclusion, olaparib is effective and well tolerated in the real-world setting of ovarian cancer treatment. Platinum sensitivity is positively correlated to the effectiveness of olaparib in both maintenance and active treatment.©2021 American Association for Cancer Research.