Objective:To explore the effect of combined ARM and FNAC on postoperative lymphedema in ALND. Methods:This study was performed from Jan 2013 to Dec 2013 and patients undergoing ALND were enrdled. The patients were devided into control and treatment groups. One ml of Carbon Nanoparticles intradermally was injected in the ipsilateral upper extremity. FNAC was performed in both groups. All the dyed nodes were dissected in the control group. ARM nodes which were positive for malignancy,suspicious,or inadequate for diagnosis were dissected,while negative ARM nodes were spared. Data were collected with successful identification and protection of the arm lymphatics,and occurrence of lymphedema. Results:Of the 72 patients undergoing ALND,in 100% of patients,all ARM lymphatics and nodes were identified in the axilla. One,3,6 patients in control group and 2,2,9 with selective group had positive,suspicious and Unidentified ARM nodes by FNAC,respectively. Two in control group and 3 with the other had positive ARM nodes by histological diagnosis. Lymphedema in two weeks and postoperative 6 months happened in 88.6% and 31.4% of control,84.6% and 30.8% in the selective patients whose ARM nodes were removed,but 12.5% and none in the selective patients whose ARM nodes were preserved. other 8 cases whose blue lymphatics and nodes were preserved. Conclusion:ARM and FNAC can safely and effectively identify the upper extremity lymph drainage,so may be used to prevent the lymphedema after ALND.