Hypertrophic obstructive cardiomyopathy (HOCM) is the most common hereditary heart disease with an incidence of about 0.1-0.2% and is a common cause of sudden death in young people. 1961 Morrow et al. first reported that resection of part of the hypertrophic septal muscle tissue to reduce left ventricular outflow tract obstruction could significantly improve clinical symptoms and hemodynamics. This article summarizes the clinical experience of 13 patients with hypertrophic obstructive cardiomyopathy who underwent extended Morrow surgery in recent years. The patients all had successful surgery. HOCM is a special type of hypertrophic cardiomyopathy, also known as idiopathic hypertrophic subaortic stenosis (IHSS), named mainly because of its hypertrophic myocardium causing left ventricular outflow tract obstruction.The lesion of HOCM is characterized by asymmetric hypertrophy of the ventricular septum, with the septum protruding into the left ventricle and the anterior mitral valve leaflet shifting toward the hypertrophic septum during systole causing left ventricular outflow tract stenosis, obstruction and mitral regurgitation, and The disease is also associated with increased systolic function, abnormal diastolic function, and myocardial ischemia. The diagnosis of this disease currently relies mainly on cardiac ultrasound, which can clarify the location and thickness of the hypertrophic muscle, the pressure difference across the stenosis, the presence of anterior mitral leaflets and the degree of mitral regurgitation, which is a guide for surgery, and intraoperative esophageal ultrasound can monitor the effect of surgery and exclude the possibility of septal perforation. In addition, in recent years, MR dynamic reconstruction can bring more intuitive results to the operator and provide more precise and detailed guidance for surgery. There are several approaches to the treatment of patients with HOCM depending on the severity of the disease. Many asymptomatic patients with a trans-stenotic pressure difference <30 mmHg have a good clinical course and a normal life expectancy and do not require therapeutic intervention. Patients with only mild symptoms can be managed with medications such as betalactam and calcium antagonists, and can also be treated with atrial sequential pacemakers or interventional methods such as injecting anhydrous alcohol into the hypertrophic septum. However, in patients with moderate or severe symptoms, surgical intervention should be considered when pharmacological treatment and other methods are ineffective to reduce outflow tract obstruction, relieve symptoms and prevent complications. The indications for surgical intervention are (1) clear diagnosis and no significant improvement by drug treatment. (2) Those with a history of syncope or trans-stenosis pressure difference >50mmHg with significant symptoms. （In 1961, Morrow reported for the first time that resection of part of the hypertrophic septal muscle tissue to reduce left ventricular outflow tract obstruction could significantly improve clinical symptoms and hemodynamics, and since then Morrow’s operation has been widely used as a classic surgical resection method. However, in recent years, some scholars have found that the main reason for recurrent stenosis after surgery is incomplete excision of hypertrophic muscle, so some authors advocate the use of expanded Morrow. In our patients, Morrow’s enlargement was used to remove the hypertrophic muscle to the apex, and the width could be from the right coronary to the left noncoronary junction, and the thickness of the septum was close to normal after resection, and transesophageal cardiac ultrasonography was performed intraoperatively to assess the morphology of the left ventricular outflow tract and the presence or absence of mitral valve anterior displacement, and the left ventricular outflow tract pressure and aortic pressure were measured directly to calculate the pressure difference to ensure a satisfactory surgical outcome. The Konno procedure is also a method to enlarge the ventricular septum to relieve stenosis, but it is less commonly used because of the large number of injuries and complications. In patients with diffuse hypertrophic obstruction, a heart transplant is required. HOCM is often associated with mitral regurgitation and anterior systolic leaflet anterior displacement. In such patients, mitral valve problems need to be addressed simultaneously, and mitral valvuloplasty is feasible in most patients. The mortality rate of septal hypertrophy muscle resection alone has been reported to be less than 1% in the literature, and 5% if coronary artery bypass or mitral valvuloplasty/replacement is performed at the same time.