The shaking of the hands may be caused by physiological factors such as overexertion and nervousness, or it may be caused by idiopathic tremor or Parkinson’s disease. 1. Physiological factors: if overwork, nervous tension, strenuous exercise, may lead to temporary local muscle spasm, appearing hand straightening will be shaking, this kind of situation is a normal phenomenon. 2. Idiopathic tremor: The cause of idiopathic tremor is not yet clear, and it may be caused by genetic and environmental factors. Symptoms usually start with tremor of the upper limbs, which may be accompanied by shaking of the hands, and may also affect the head and neck, voice, legs or trunk. 3. Parkinson’s disease: Parkinson’s disease may be caused by genetic, environmental, and neurological aging factors. Symptoms such as tremor, muscle tonus, and bradykinesia may occur, which may be manifested by shaking of the hands when they are straightened out. There are many causes of hand tremor, it is recommended to find out the cause of the disease in time, and actively cooperate with the doctor to take relevant treatment measures, so as to avoid delaying the condition.