Abstract: Fourteen cases of brachial olexus lesion are reported, in which 49 nerve were examined for EMG, SSCV and SSEP. The results of SSEP determination were compared with the average values in 60 normal subjects. The results suggest that MCV is useful in determining the degree and distribution of nerve lesions; SSEP is of value in determining the continuity of the sensory conduction; both SSEP and SSCV are of some help in localizing lesion areas, which may be preor post-ganglion. By combining of all those methods reliable results can be obtained. The results also shows that multiple nerves should be examined in determining brachial plexus lesions.