The purpose of this study is to compare nifedipine controlled-release (CR) tablets (Xin Ran) with nifedipine controlled-release tablets (Adalat）in the treatment of mild to moderate essential hypertension.

Inclusion Criteria:

• Voluntarily participate and must sign informed consent form
• Mild to moderate essential hypertension (SBP 140-179 mmHg and/or DBP 90-109 mmHg)
• Average DBP measured by 24-hour ambulatory blood pressure monitoring (ABPM) ≥80 mmHg

Exclusion Criteria:

• Secondary hypertension and malignant hypertension
• Pregnant or nursing women, or patients that cannot guarantee to take effective contraception measures
• Baseline SBP≥180 mmHg or DBP≥110 mmHg, or patients with cerebral, cardiac or renal complications
• Have following complications: cerebrovascular accident within 6 months, myocardial infarction or cardiac failure, macroaneurysm or dissecting aneurysm, definite angina, A-V block of grade 2 or higher, sick sinus syndrome, atrial fibrillation or other malignant arrhythmia
• Clinical significant diseases of heart, lung, liver, kidney and hematologic system or malignant tumors, HIV infection, uncontrolled diabetes (fasting blood glucose ≥7.0 mmol/L, 2-hour postprandial blood glucose ≥7.8 mmol/L)
• Kock pouch
• Sever gastrointestinal stenosis
• Abnormal laboratory values with clinical significance, including serum potassium <3.5 or >5.5 mmol/L, glutamic-pyruvic transaminase (ALT) or glutamic oxalacetic transaminase (AST) >2-fold upper limit of normal (ULN), Cr >ULN
• Uric acid >ULN with the diagnosis of gout
• Gastrointestinal abnormalities or surgery that may interfere with drug absorption
• Hyperthyroidism or hypothyroidism
• Allergic to any ingredient or metabolite of investigational drug or drugs of similar structure
• Heavy smokers (>25 cigarettes every day), alcoholics (>250 ml liquor every day), drug addicts
• Psychological diseases, acrasia, cannot express explicitly
• Patients whose mood may be affected by variations in blood pressure, which in turn increases blood pressure
• Anxiety disorders, depression or cannot follow study protocol
• BMI >30
• Night shift, irregular sleep patterns or insomnia
• participate in other clinical trials within 3 months
• other conditions that investigators consider unsuitable for participation