The appearance of hand tremor at the age of 40 requires consideration of the following causes: 1, idiopathic tremor: also called primary tremor, is a kind of involuntary motor disease with tremor as the main manifestation only. It starts between 40-60 years old, 1/3 of patients have a family history, and there are no other abnormal clinical manifestations besides tremors; 2, Parkinson’s disease: Parkinson’s disease can also appear around 40 years old if the age of onset is early, the tremors are resting tremors, the symptoms are reduced after exercise, the symptoms are aggravated when emotional tension and anxiety, and the symptoms disappear after sleep. In addition to shaking, there is often stiffness and inactivity of the limbs; 3, hyperthyroidism: this condition is mostly seen in young people, hyperthyroidism leads to increased neural excitability, often producing postural tremor of the hands. The tremor is more obvious in a certain hanging posture or when performing fine movements.