Subclinical hypothyroidism is a very common clinical endocrine metabolic disorder that is characterized by normal serum thyroid hormone levels but elevated thyrotropin (TSH) levels. Subclinical hypothyroidism can be clinically asymptomatic and only detected during physical examination, or it can present with a variety of symptoms similar to clinical hypothyroidism, such as fatigue and coldness, only to a lesser extent. In recent years, with the continuous improvement of TSH testing methods, the detection rate of subclinical hypothyroidism has also shown a significant increase. As the number of patients with subclinical hypothyroidism increases, many patients want to know whether subclinical hypothyroidism needs to be treated. Whether subclinical hypothyroidism needs treatment clinically actually depends on the level of TSH. We can classify patients with subclinical hypothyroidism into three categories according to their TSH levels: The first category of patients with subclinical hypothyroidism has TSH levels of 3-5 mIU/L. For this category of patients, treatment is generally not recommended, but thyroid function needs to be rechecked after one year, especially for patients with positive thyroid autoantibodies including thyroglobulin antibody (TgAb) and thyroid peroxidase antibody (TPOAb). Patients with subclinical hypothyroidism. The second group of patients with serum TSH levels between 5.0 and 10 mIU/L is the most common group of patients in clinical practice, and the treatment of these patients is the most controversial. In addition to regular monitoring of thyroid function, drug therapy can be considered in the following cases: 1) female patients who are pregnant or intend to become pregnant, because it has been confirmed that if subclinical hypothyroidism in women is not treated, the rate of adverse pregnancy events such as preterm delivery and miscarriage is higher in mothers than in women with normal thyroid function, and the IQ of the child will also be affected after birth; 2) patients with goiter. The enlarged thyroid gland can often be relieved after taking medication; 3. Patients with clinical symptoms of hypothyroidism such as weakness and fatigue, some of which can disappear or be reduced after taking medication; 4. Patients themselves strongly request medication; 5. According to the age of the patients, young people such as children and adolescents advocate treatment; 6. Patients with TSH greater than 8mIU/L in both serum tests; 7. Patients with positive thyroid autoantibodies, because Patients with positive thyroid autoantibodies are more likely to become clinically hypothyroid according to their age; 8. Patients with psychiatric symptoms such as affective disorders and depression, which may improve after medication; 9. Patients with progressive increase in TSH detection; 10. Patients with clinical infertility and ovulation dysfunction; 11. Patients with dyslipidemia such as hypercholesterolemia. The third category of patients with subclinical hypothyroidism has TSH levels above 10 mIU/L. For these patients, clinical treatment with medication is recommended. In conclusion, whether a patient with subclinical hypothyroidism needs treatment or not should be decided by an endocrinologist according to the specific situation of each patient.