In this research, the investigators aim to compare the antihypertensive efficacy and safety of monotherapy of routine dose angiotensin receptor antagonist telmisartan (ARB) and diuretic Hydrochlorothiazide (HCTZ) in high sodium intake patients with mild to moderate hypertension. The research will be conducted in the rural area in Hebei province, where people have a high sodium diet in their daily life. The 1200 eligible subjects will be drawn from 12 local county-level hospitals. Subjects will be randomly allocated in double-blind manner into ARB or HCTZ group to be administered telmisartan 40mg per day or hydrochlorothiazide 25mg per day respectively. After two-month treatment, the investigators will evaluate and compare the antihypertensive efficacy and safety between the two therapies.