Inclusion Criteria:  1.40-75 years old (inclusive); 2. Patients who have been diagnosed with all types of essential hypertension (those who are currently taking antihypertensive drugs with normal blood pressure can still be admitted) or those whose blood pressure screening meets the inclusion criteria; 3. Plasma (or serum) Hcy 10 mol/L; 4. Enalapril folic acid tablet 10.8 mg/day alone is not up to standard; 5. In the case of women of reproductive age, agree to use a reliable method of contraception during the trial; 6. Participate voluntarily and sign the informed consent;  Exclusion Criteria:  1. Previous stroke with definite diagnosis; 2. Patients with previous well-diagnosed myocardial infarction; 3. The presence of well-diagnosed heart failure; 4. Postoperative revascularization; 5.DBP >=110 mmHg or SBP >=180 mmHg; 6. Confirmed secondary hypertension; 7. Severe physical and systemic disease, which is estimated to be unable to complete the follow-up; 8. People with known congenital or acquired organic heart disease; 9. People who have had obvious intolerable adverse reactions to ACEI drugs in the past; 10. Have contraindications to ACEI drugs (including renal failure) or are allergic to the drugs used in the study or other ingredients in the drugs; 11. According to the researchers, there are contraindications to the use of folic acid; 12. Pregnant and lactating women; 13. If there are other obvious laboratory tests, abnormal physical signs and clinical diseases, it is not suitable to participate in the study according to the researcher's judgment; 14. Unwilling to participate in the trial, unwilling or unable to change the existing medication regimen; 15. Long-term use of folic acid or health medicines containing folic acid; 16.Severe mental disorder, unable to express their will