The primary purpose of the study is to estimate the target organ protection after 12 months of antihypertensive treatment in masked hypertension patients with at least one kind of target organ damage (left ventricular hypertrophy, large arterial stiffness and microalbuminuria). Improvement was defined as the relevant parameter back to normal or declined at least 20%.

The secondary objectives include: blood pressure lowering effect, target organ damage parameters improvement, and the incidence rate of all cause death and cardiovascular events (stroke and myocardia infraction).

Inclusion Criteria:

1. Age 30-70 years old
2. Masked hypertension patients, defined as clinic BP<140/90 mmHg, while 24h ambulatory BP ≥130/80 mmHg and (or) daytime BP ≥135/85 mmHg and (or) nighttime BP ≥120/70 mmHg
3. Combined with at least one kind of target organ damage: left ventricular hypertrophy (Cornell voltage combination ≥2440mm·ms or Sokolow-Lyon index ≥4.0mv for male and 3.5mv for female), large arterial stiffness (brachial-ankle pulse wave velocity ≥1400cm/s) and microalbuminuria (twice random urine microalbuminuria/creatinine ratio ≥2.5mg/mmol for male and 3.5mg/mmol for female).
4. Didn't use any anti-hypertension drugs within 2 weeks
5. Be willing to participate in the trials and able to finish clinic visits

Exclusion Criteria:

1. Under antihypertensive treatment
2. Secondary hypertension
3. Taking other medications that may influence BP
4. Sleep apnea syndrome
5. Diabetes combined with microalbuminuria
6. Renal parenchymal disease, such as chronic nephritis, polycystic kidney
7. Occurrence of coronary heart disease, myocardial infraction or stroke within 6 months
8. Structural heart disease, such as hypertrophic cardiomyopathy, dilated cardiomyopathy
9. Alanine transaminase (ALT), aspartate transaminase (AST), total bilirubin (TBL) upper the twice of normal range, serum creatinine (Scr)≥2.0mg/dl, plasma hypokalemia≥5.5mmol/L,
10. Patients have contraindications to angiotensin receptor blockers (ARBs)