Aim To investigate the feasibility and effectiveness of 3D printing and extracorporeal membrane oxygenation assistant in transcatheter aortic valve replacement (TAVR) of severe aortic stenosis patients. Methods From November 2018 to May 9,0 patients with severe aortic stenosis underwent transcatheter aortic valve replacement assisted by ECMO in Xijing Hospital of Air Force Military Medical University. The preoperative left ventricular ejection fraction (LVEF) was (30.3%±10.5%). The preoperative cardiac function grade of all patients was Ⅳ grade(NYHA). Before operation, CT data of all patients were collected and reconstructed. Their cardiovascular models were made by using 3D printing technology. All preoperative evaluation, operation scheme determination and preoperative conversation were done with 3D printing models. Results All the 10 patients received TAVR successfully. The hemodynamic indexes were stable in the perioperative period. The operation time was (192.5±30.3) min, and the DSA irradiation time was (40.5±3.2) min. The ECMO assistant time was (60.5±23.9) min. The echocardiography showed the heart function was improved. The LVEF was (48.5%±4.3%). Conclusion It is very difficult for patients with very high-risk aortic stenosis to be treated with TAVR. 3D printing technology can provide doctors and nurses an intuitive model, assist doctors-patient communication and preoperative evaluation. ECMO can ensure the perioperative hemodynamic stability of patients and provide effective cardiopulmonary function support, thus to improve the success rate of TAVR.