Inclusion Criteria:  Patients diagnosed with metabolic syndrome aged 40-75 years old. Metabolic syndrome was defined according to the Chinese Guidelines for the Prevention and Treatment of Dyslipidemia in Adults (revised edition 2016). Subjects will be diagnosed with metabolic syndrome when meeting three or more of the following items: 1, central obesity and/or abdominal obesity (waist circumference ≥90cm for men and ≥ 85cm for women); 2, hyperglycemia (fasting blood glucose ≥6.10 mmol/L or two-hour blood glucose ≥7.80 mmol/L in glucose tolerance test); 3, hypertension: blood pressure ≥130/85 mmHg and/or diagnosed hypertension under treatment; 4, fasting triglyceride ≥1.7 mmol/L (150mg/dl); 5, fasting HDL cholesterol<1.0 mmol/L.  Exclusion Criteria:  Previously diagnosed diabetes. Baseline LDL cholesterol≥130mg/dl (3.4mmol/L). Baseline triglyceride≥500mg/dl (5.6mmol/L). Baseline blood pressure ≥140/90 mmHg (twice not on the same day). Impaired liver function, have obvious clinical signs or symptoms of liver disease, acute or chronic hepatitis, alanine/aspartate aminotransferase levels >3 times the upper limit of the reference range at the screening visit. Renal dysfunction (glomerular filtration rate<45ml/min) Patients ventilated by ventilator. Hypersensitivity to berberine. Disease which may cause tissue hypoxia (especially acute disease, or worsening of chronic respiratory disease). Severe chronic gastrointestinal disease. Severe psychiatric illness. Cancer requiring treatment in past 5 years. Women who are pregnant or breastfeeding . Participation in another clinical trial within the past 30 days . Other significant disease that in the Investigator's opinion would exclude the subject from the trial.