Bevacizumab can bind to vascular endothelial growth factor to form a recombinant human monoclonal IgGl antibody. Its application in the treatment of malignant tumors with chemotherapy has an effect on the clinical effect and the incidence of adverse reactions of patients. The clinical application value of bevacizumab was analyzed. The results showed that the total control rate of clinical treatment in the observation group was 96.6% and 73.3% in the control group was significantly higher than that in the control group (p < 0.05). The main adverse reactions of the two groups were hemorrhage, hypertension, proteinuria and venous thromboembolism. The clinical adverse reactions of the observation group were significantly lower than those of the control group. In conclusion, bevacizumab can significantly improve the clinical efficacy and reduce the incidence of adverse reactions in patients with malignant tumors during chemotherapy. The combination of bevacizumab and chemotherapeutic drugs is still the main direction of clinical application.