A 50-year-old woman was admitted to the hospital because of chest pain accompanied with cold sweating, palpitation and extremely high blood pressure. Transthoracic echocardiography (TTE) revealed systolic anterior motion of mitral valve, with peak velocity crossing the left ventricular outflow tract (LVOT) about 4.9 m/s and severe mitral regurgitation (MR). The study for secondary hypertension revealed high urine vanillylmandelic acid (82.57 mg/24 hrs) and norepinephrine (916.5 ug/24 hrs). A huge pheochromocytoma was found by abdominal computed tomography and magnetic resonance imaging. During the hospitalization, her blood pressure could fluctuate from 188/122 mmHg to 89/46 mmHg, depending on fluid challenge, within three hours with chest pain and cold sweating. Thus, we decided to apply alcohol septal ablation therapy to provide a more stablehemodynamic status for tumor resection. TTE was done one week post alcohol septal ablation and showed the peak velocity crossing the LVOT declined to 2.3 m/s and only mild MR. Subsequently, the patient successfully received surgical resection and was discharged under long-term outpatient clinic follow-up.