Objective To investigate the effect of thoracic epidural block of 0.2％ ropivacaine combined fentanyl on patients undergoing the operation of breast cancer. Methods 80 patients with breast cancer were randomly divided into the observation group ( received 0.2％ ropivacaine plus fentanyl epidural anesthesia) and the control group (received 0375％ ropivacaine epidural anesthesia). The onset time of sensory block and effect of epidural block were accessed. Hemodynamic parameters were monitored and artery blood gas was measured. The side effects if any were recorded.ResultsThere were no respiratory and circulatory depression in the observation group. The onset time of sensory block and effect of anesthesia were similar between the two groups (P＞0．05). There were significant differences on hemodynamic parameters and oxygen saturation between the two groups. Conclusion Epidural ropivacaine combined fentanyl can be used safely for radical mastectomy on patients undergoing the operation of breast cancer.