Objective To investigate the effects of new-onset left bundle branch block (new-LBBB) on hemodynamics and prognosis after transcatheter aortic valve placement (TAVI). Methods The data of 245 severe aortic stenosis patients who underwent TAVI from Mar. 2013 to Apr. 2018 in the Second Affiliated Hospital, Zhejiang University were retrospectively analyzed. Patients were divided into control group (188 cases) and new-LBBB group (57 cases) based on whether they had new-LBBB or not after TAVI. The baseline data were collected at admission, and the echocardiographic results were analyzed at preoperation and 12 months postoperation. The study endpoint was all-cause death, and the follow-up deadline was Apr. 30, 2019. Survival analysis was performed by Kaplan-Meier method and log-rank test. Results There were no significant differences in mitral regurgitation score or left ventricular ejection fraction (LVEF) between the two groups before operation (both P>0.05); 12 months postoperation, the LVEF of the new-LBBB group was significantly lower than that of the control group (59.20%[53.70%, 64.58%]vs 64.90%[60.17%, 68.45%]), and the mitral regurgitation score was significantly higher than that of the control group (1.16[0.44, 1.84]vs 0.82[0.27, 1.46]) (Z=-4.267, -2.668, both P<0.01). After 35.77 (23.80-45.88) months of follow-up, the mortality rate of the new-LBBB group was 10.5% (6/57) and that of the control group was 5.9% (11/188), with no significant difference (χ²=1.48, P=0.238). Conclusion New-LBBB after TAVI can affect LVEF, induces or aggravates mitral regurgitation, but has no influence on 1-year survival rate.