The purpose of this study is to investigate the effects of rosuvastatin treatment on degree of intracranial arterial stenosis in two years. Dyslipidemia patients with intracranial arterial stenosis will be enrolled under informed consent in this study. Rosuvastatin (5mg) will be orally administered once daily. Dose of rosuvastatin will be adjusted to control serum LDL-c level under 1.8mmol/L. Primary outcome is the progression of intracranial stenosis on magnetic resonance angiography (MRA) after two years.