The common clinical causes of hand writing are Parkinson’s disease, pharmacogenetic tremor, and emotional abnormalities. 1. Parkinson’s disease: this is a common clinical degenerative disease of the nervous system in the elderly, usually associated with the environment, the aging of the nervous system, genetic factors, clinical manifestations of hand tremor at rest, muscle tonus, difficult postural balance, motor retardation and so on. 2. Pharmacogenic tremor: this disease refers to the tremor caused by drugs, such as chlorpromazine, haloperidol, phenazopyridine and other antipsychotics, the sick people in the use of drugs or increase the dose of drugs are prone to extrapyramidal symptoms, such as tremor of the hands at rest, muscle contraction abnormalities, and so on. 3. Emotional abnormalities: some people may experience hand tremor due to emotional instability, such as extreme sadness, agitation, anxiety, etc. This is a physiological change. This is a physiological change, and the symptoms can be relieved after stabilizing emotions. If the above situation exists, it is recommended to consult a doctor for a clear diagnosis and further treatment.