Purpose As a third-generation EGFR TKI has been taken orally, Osimertinib effectively inhibits mutant EGFR, including T790M EGFR resistance mutations. Here, we examined real-world efficacy and tolerability of Osimertinib among Chinese patients with advanced EGFR T790M-mutant NSCLC. Patients and Methods A total of 106 advanced NSCLC patients who were taking Osimertinib following disease progression after EGFR-TKIs or other treatments were retrospectively recruited in this study. The PFS and OS after Osimertinib treatment were analyzed as the primary endpoints. Results Osimertinib was used as a second line and ≥3rd line treatment in 22.6% and 77.4% of the patients, respectively. DCR and ORR were 93.4% and 57.5%, respectively. Median PFS was 12.4 12 (95% CI, 10.5–13.5) months. The PFS was 11 (8.0, 14.0) and 12 (10.3,13.7) months ( p = 0.373), in patients with and without CNS metastasis, respectively. PFS in 2nd and ≥3rd line treatment was 11 (9.0, 13.0) and 12.4 12 (8.9, 15.1) months ( p = 0.799), respectively. In patients with EGFR exon 19 deletion and exon 21 L858 mutation, the median PFS was 11 (9.2, 12.8) and 12 (9.2, 14.8) months, respectively ( p = 0.833). Median PFS in the monotherapy group and combined anti-angiogenesis group was 11 (9.9,12.1) and 14 (11.2,16.8) months, respectively. Median OS after Osimertinib initiation was 27 (19.6, 34.4) months: 15 (6.9, 23.1) and 27 (22, 32) months in patients with and without CNS metastasis (p=0.027), 27 (20.3,33.7) months and (undefined) as second line or ≥3rd line of treatment ( p = 0.421), respectively. In patients with exon 19 deletion, the median OS was not reached, and in patients with exon 21 L858 mutations, the median OS was 23 (19.1,29.9) months (p=0.027). Median OS in the monotherapy group was 27 (21.7,32.3) months, and in combined anti-angiogenesis group was not reached (p=0.68). Conclusion Osimertinib can effectively treat advanced NSCLC with T790M mutations independently of previous treatment lines.