A prosthesis (100) for preventing a valve regurgitation, comprising a fixation unit (110), a connection piece (120) and a closure assisting piece (130); the fixation unit (110) comprises a fixation piece (111) and an anchor (112); the connection piece (120) is flexible, and a distal section thereof is connected to a proximal section of the fixation piece (111), and a proximal section thereof is connected to a distal section of the closure assisting piece (130); the fixation piece (111) is fixed on the atrial wall or a valve ring of a patient via the anchor (112); the deployed width of the fixation piece (111) is less than two-thirds of the circumference of a valve tissue annulus; the closure assisting piece (130) is located between autologous valve leaflets of the patient when in a free state; the maximum width of the closure assisting piece (130) is less than the maximum deployed width of a single autologous valve leaflet; and the proximal end of the anchor (112) is provided with an anti-disengagement end (1120). The position of the prosthesis (100) can be adjusted, and the prosthesis (100) is accurately positioned and firmly anchored, and does not readily adhere to tissue adjacent to the valve annulus of the patient.