To determine the efficacy of the HS-25 (10mg or 20mg) or in combination with Atorvastatin (10mg)in reducing low density lipoprotein-cholesterol (LDL-C) levels after a 12-week period of treatment in adults with primary hypercholesterolemia; To determine the safety of HS-25 (10mg or 20mg) or in combination with Atorvastatin (10mg)in subjects with LDL-C after a 40-week period of treament.

This is a 12-week, randomized, double-blind, double dummy, placebo-controlled study designed to assess the effects of the cholesterol absorption inhibitor HS-25 (10mg or 20mg) or in combination with Atorvastatin (10mg) on LDL-C levels in adults who have untreated LDL-C levels ranging from 3.36-4.88mmol/L(130-189 mg/dL)and fasting triglyceride levels < 350 mg/dL. Eligibility is restricted to 18-70 years old men or women who are using a highly effective birth control method or are not of childbearing potential;subjects with not treated by statins in six months before signature of the informed consent.Subjects with diabetes, a history of myocardial infarction or other clinical evidence of atherosclerotic vascular disease or treated are not eligible for participation in the study.

Inclusion Criteria:

• Subjects who are 18 to 70 years of age, male or female using a highly effective birth control method or not of child-bearing potential, at Visit 1 (screening visit);
• LDL-C 3.36mmol/L (130 mg/dL) to 4.88 mmol/L (189 mg/dL) (inclusive) on a cholesterol lowering diet but no lipid modifying drug treatment (statins) for at least 6 weeks before signed written informed consent;
• A qualifying LDL-C value must be obtained at the beginning and end of the placebo run-in (Visit 2 and Visit 3) and the Visit 3 value must be within 12% of the value at Visit 2, higher or lower; the average of both qualifying values must be in the range of 3.36mmol/L (130 mg/dL) to 4.88 mmol/L (189 mg/dL) (inclusive) for inclusion in the study.

Exclusion Criteria:

• Liver transaminases > 1.5 x upper limit of normal.
• Homozygous Familial Hypercholesterolemia.
• Subject who was diagnosed as diabetes with aged greater than 40 years old.
• Subject who was diagnosed as diabetes with one of the following of cardiovascular risk factorss: Hypertention Bp ≥ 140/90mmHg,or smoking, or low HDL-C (1.04mmol/L), or BMI≥28kg/m2.
• Women who are pregnant or breast feeding.
• Atherosclerotic cardiovascular disease including Arteriosclerotic heart disease, Acute coronary syndrome，Coronary artery bypass graft,Coronary angioplastyPeripheral arteriosclerosis,Cerebrovascular accident - history of Severe Endiocrine disease (for example Thyroid function abnormal) - History of a positive test for human immunodeficiency virus, hepatitis B or hepatitis C.
• History of advanced cancer - Arrhythmias need to be treated by medications
• Had severe injured or surgery in 6 months before study start.
• Hypersensitive to HS-25 or place.
• History of intolerance to ezetimibe.
• Participation other studies in three months.
• Treatment with a fibric acid derivative (eg, fenofibrate, gemfibrozil), probucol, warfarin, systemic corticosteroid, cyclosporine or other immunosuppressant agent within the prior 12 weeks.