The asymmetry of the left and right arms may be caused by muscular development of one side and underdevelopment of the other, neurogenic atrophy, disuse atrophy and so on, and should be actively treated for the original disease, and at the same time improve the muscle strength. 1. Muscle development on one side and muscle underdevelopment on the other side: the common reason is that the left and right arm exercise degree is not the same, or long-term use of an arm for labor, should be underdeveloped arm strength training, so as to make the same degree of muscular development of the two arms to improve the asymmetric phenomenon. 2. Neurogenic atrophy: due to cervical spondylosis caused by nerve compression or its own nerve lesions, resulting in a lack of local muscle nerve nutrition, resulting in neurogenic atrophy. Should actively lift the nerve compression, treatment of primary disease, but also can take neurotrophic drugs such as vitamin B1, furadithiamine, olanzapine and so on. 3. Disuse atrophy: if there is a history of trauma, resulting in fractures or other injuries, braking the affected limb may lead to muscle atrophy, causing left and right arm asymmetry, the affected limb should be rehabilitated to strengthen muscle movement and strength. Found that the left and right arm asymmetry, it is recommended to go to the hospital in time for diagnosis, to exclude organic lesions, under the guidance of professionals for rehabilitation exercises.