To investigate the value of differential diagnosis by electromyography in patients with hand muscle atrophy. Methods: A total of 136 patients with hand muscle atrophy were enrolled. The results of nerve conduction, F wave, and needle electrode electromyography were analyzed. Results: Electrophysiology results showed 29 cases (21.32% ) of ulnar neuropathy, 24 cases (17.65% ) of median neuropathy, 17 cases (12.50%) of ulnar nerve with median nerve damage, 2 cases (1.47%) of cervical spondylosis, 2 cases (1.47%) of brachial plexus injury, 9 cases (6.62%) of Hirayama disease, 41 cases (30.15%) of motor neuron disease, 7 cases (5.15% ) of myopathy, and 5 cases (3.68% ) of multiple peripheral neuropathy. Conclusion: Nerve electrophysiology can be used to determine the degree and distribution of hand muscle atrophy.