The invention discloses a buffer protection method and device for a motor vehicle safety belt and aims to thoroughly solve the problem that the whipping effect in motor vehicle crash causes injury to human. A buffer protector is disposed at each fixation point of the safety belt and is in a wedge structure. The insert end of each wedge structure is provided with an elastic device so that the insert end is gradually compressed when inserted in, thus kinetic energy is converted into elastic potential. The angle of each wedge surface or the damping coefficient of an object in contact with the wedge surface is set, so that automatic release of the elastic potential is avoided. The device comprises a shell. The inner wall of the shell is provided with a slant. A sleeve is disposed in the shell. Piston-type roller carriers are disposed at two ends of the sleeve, and an elastic member is disposed between the two piston-type roller carriers. A roller is disposed in each piston-type roller carrier, and starting force of the device needs to be larger than that of a safety belt lock so that the device can play a role after the safety belt is locked.