Abstract: Objective The value of left ventricular outflow tract pressure gradient (LVOTG) was accurately assessed by studying the Doppler spectrum of left ventricular outflow tract in hypertrophic obstructive cardiomyopathy (HOCM), and then use echocardiography to evaluate the effect of percutaneous septal chemical ablation on the treatment of hypertrophic obstructive cardiomyopathy. Methods Retrospective analysis of January, 2012 to March, 2017 due to chest tightness, dyspnea and other clinical symptoms to our hospital, transthoracic ultrasound examination for hypertrophic obstructive cardiomyopathy in 19 patients, LVOTG was calculated according to the anterior and posterior peak flow rates of the specific"crab-like"spectrum of the left ventricular outflow tract, and PTSMA treatment of intracardiac catheter pressure and echocardiography measured LVOTG values were compared. The frequency of second peak flow and mitral regurgitation were analyzed in 12 patients without PTSMA and 7 patients underwent PTSMA, and patients with PTSMA before and after the"crab like"second peak flow rate and the mitral regurgitation velocity were compared and analyzed to evaluate the effect of PTSMA. Results All patients with left ventricular outflow tract were measured specific"crab-like"spectrum and ventricular septal thickening (13-23 mm) are accompanied by varying degrees of mitral regurgitation (mild to moderate) and the forward movement of the valve (SAM sign). The results of the second peak flow velocity measured by echocardiography were analyzed by the paired sample t test. The difference between the pressure gradient and the left ventricular catheterization was not statistically significant. After PTSMA treatment of patients, the LVOTG and obstruction decreased, mitral regurgitation rate is also accordingly reduced. Conclusion The second peak velocity of the"crab like"spectrum measured by the velocity of the left ventricular outflow tract can be used to measure the pressure difference, and to select the appropriate treatment for the clinical treatment of HOCM.