Objective To discuss the reasens,prevention and treatment of subcutaneous hydrops after radical mastectomy of breast cancer.Methods 110 cases of breast cancer patients were selected and divided into two groups randomly;observation group and contral group.All patients were given compression bandaging,twin-tube suction drainage.The drainage tube were removed on 6,9 days respectively in the observation group;and the drainage tube were removed on the six day conventionally in the control group,the two groups were compared.Results The rate of subcutaneous hydrops was 6.2 % in observation group after operation and the rate of subcutaneous hydrops is 20 % in control group,there are obvious difference.Conclusion Compression bandaging,twin-tube drainage with negative pressure,removeal of drainage tube respectively can reduce the occurrence of subcutaneous fluid after radical mastectomy.