The left hand has strength and the right hand has no strength, which may be caused by overwork, cervical spondylosis, acute injury, cerebrovascular lesions and other factors. 1. Overwork: prolonged use of the right hand to lift heavy objects may lead to excessive fatigue of the right limb, which will make the right hand has no strength and the left hand has strength, and can be gradually improved after reasonable rest. 2. Cervical spondylosis: prolonged over-lowering of the head may induce cervical spondylosis, which may cause compression of the nerves innervating the right limb, resulting in a lack of strength in the right hand, which may be accompanied by radiating pain in the right limb, numbness of the right limb and other symptoms. 3. Acute injury: Acute injury to the right hand, localized fracture, such as wrist joint fracture, can lead to the right hand has no strength, accompanied by pain, swelling and other symptoms. 4. Cerebrovascular lesions: for example, acute cerebral infarction or acute cerebral hemorrhage, in the acute attack, it will lead to the right hand has no strength, may also be accompanied by lower limb weakness, headache and dizziness, nausea, vomiting and other symptoms. The phenomenon of having strength in the left hand and no strength in the right hand lasts for a long time and is accompanied by other clinical symptoms, so it is recommended to consult a doctor for timely examination and treatment in order to avoid continuous aggravation of the lesion.