Objective To investigate the effect of early pressure gradient (PG) after transverse aortic constriction(TAC) on the degree of aortic constriction and aortic pressure in mice, the relationship with myocardial hypertrophy and myocardial systolic function at the experimental endpoint, and to provide a basis for the early measurement of aortic constriction and selection of experimental mice. Methods Male C57BL/6 mice aged 14~16 weeks were selected for TAC surgery. Cardiac echocardiography was performed before and 1 week and 4 weeks after the operation, and hemodynamic testing and measurement of body weight and left ventricular weight/ tibial length (LV/ TL) were performed 4 weeks after surgery. Results Both flow velocity and PG were significantly higher 1 and 4 weeks after TAC compared with preoperative levels (P< 0. 05). PG at 4 weeks after TAC was significantly correlated with left ventricular systolic pressure (r=0. 773, P< 0. 001) and systolic blood pressure (r= 0. 658, P= 0. 002), indicating that hemodynamic testing by noninvasive ultrasound Doppler can replace the invasive hemodynamic detection of pressure caused by TAC. The PG 1 and 4 weeks after TAC was significantly and positively correlated with LV/ TL, left ventricular mass index, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, left ventricular anterior wall thickness at diastole, and left ventricular posterior wall thickness at diastole. In addition, both 1 week and 4 weeks after TAC, the ejection fraction and fraction shortening were significantly negatively correlated with PG. Conclusions The PG 1 week after TAC predicted the degree of myocardial hypertrophy 4 weeks after TAC, and the larger the PG, the heavier the left ventricular weight, the more severe the ventricular wall thickness and ventricular dilation 4 weeks after TAC, and the more severe the impairment to myocardial systolic function.