Abstract: Objective:To investigate the efficacy of bevacizumab on the treatment of serious peritumorous brain edema. Methods:A total of 16patients with malignant brain tumors and serious peritumorous brain edema, ( 13cases of lung cancer, 2 cases of breast can -cer, and 1 case of recurrent glioblastoma) were analyzed. Treatment with glucocorticoids, osmotic dehydration, and other convention-al approaches were not effective for these patients. Bevacizumab was administered at a dose of 5 mg/kg at least once every three or four weeks. The Karnofsky performance score (KPS) and the changes in cerebral edema symptoms, such as cerebral edema volume, tu -mor volume, edema index (EI), and changes in magnetic resonance imaging (MRI) were compared before and after treatment. The t-test and least-significant difference method were used to compare treatment groups. Results:All bevacizumab-treated patients had re-duced symptoms. The KPS after treatment was significantly higher than that before treatment (P<0. 001 ). The cerebral edema vol -umes, tumor volumes, and EI of16patients were significantly decreased ( P<0. 05). Bevacizumab caused mild clinical side effects. Con -clusion: Preliminary results showed that treatment of serious peritumorous brain edema with bevacizumab was safe and effective.