Efficacy and the frequency of tumor cavitation have not been investigated in patients with metastatic colorectal cancer (mCRC) and lung metastases (LMs) treated with chemotherapy in combination with bevacizumab. This study was aimed to evaluate the efficacy and safety of bevacizumab for unresectable mCRC with LM and to determine the frequency of tumor cavitation, and its correlation with clinical outcomes in patients receiving bevacizumab plus chemotherapy. Patients with mCRC and LMs treated with bevacizumab as first- or second-line therapy at West China Hospital, Sichuan University Cancer Center from September 2010 to November 2016 were included in this retrospective study. Data on clinicopathological characteristic were collected and overall survival (OS), progression-free survival (PFS), objective response rate (ORR) and disease control rate (DCR) were determined. Among 60 patients included in the study, response rate (RR), stable disease (SD), and DCR were 43.6% (17/39), 51.3% (20/39) and 94.9% (37/39) in patients receiving bevacizumab as first-line treatment. Median OS and PFS of the first-line treatment group were 32.4 and 15.5 months, respectively. Among 60, 12 patients (20%) developed cavitation after bevacizumab therapy initiation. Median OS was longer in patients with cavitation than those without cavitation (42.1 vs 30.8 months; p = 0.042) in the first-line treatment group. Bevacizumab in combination with chemotherapy exhibited promising efficacy in mCRC patients LMs. Moreover, our findings reveal that OS might be affected by new tumor cavitation during antiangiogenic agent treatment.