A left ventricular assist device includes an outer tube, which includes a ventricle section located in the left ventricle and an artery section located in the aorta, the ventricle section is provided with first suction meshes, and the artery section is provided with first discharge meshes, and the outer tube is in communication with an external drive device a ventricular-side suction component provided in the ventricle section and a discharge-section balloon catheter, is provided with second discharge meshes, and the second discharge meshes and the first discharge meshes are arranged to be staggered and not overlapped. With the suction and inflating of the external drive device, blood is sucked into the outer tube from the left ventricle by the ventricular-side suction component, and forced out of the outer tube into the aorta by the discharge-section balloon catheter, to pump blood in the left ventricle into the aorta.