Electromyography is the science of studying the electrical activity of nerve and muscle cells, and EMG refers to the recording of electrophysiological properties of muscles in the quiet and contracted states, and generally includes both broad and narrow meanings: narrow EMG is also known as concentric needle or conventional EMG; while broad EMG includes neuroelectromyography or known as nerve conduction velocity, repetitive nerve electrical stimulation, various reflexes, single fiber EMG, giant EMG, scanning EMG, surface EMG, evoked potential EMG, and motor unit counting. The specific tests are often adjusted and determined according to the clinical presentation and impression of the patient. Since the First International Conference on Electromyography in Pavia (Italy) in 1961, after the research and pioneering of scholars such as JunKimura, it was found that EMG examination has an important value in the diagnosis, efficacy assessment and prognosis evaluation of neuromuscular diseases. Foreign scholars even proposed – EMG is an extension of neurological examination. Indications and significance of EMG examination: I. Indications: lesions below the anterior horn cells including anterior horn cells II. Clinical significance: 1. detect subclinical lesions or lesions that are easily overlooked early diagnosis of motor neuron disease, deep muscle atrophy and mild paralysis 2. diagnose and differential diagnosis neurogenic damage, myogenic damage, neuromuscular junction lesions, myelin damage, axonal damage 3. provide clinical localization and diagnosis of Based on upper motor neuron lesion, lower motor neuron lesion, extensive lesion, segmental lesion, single nerve damage, multiple nerve damage, neuronal damage, nerve root damage, nerve trunk damage, nerve terminal damage, etc. 4.Judgment of disease and prognosis evaluation 5.Efficacy assessment.