A displacement scanning-based three-dimensional display device (1), comprising: a protection shell (10), a projection screen (11), light-shielding shells (120, 121), two rotating shafts (13), a conveyor belt (14), at least two scatter plates (15). The rotating shafts (13) rotate at a high and constant speed; the scattering plates (15) fixed on the conveyor belt (14) periodically receive image slices projected from the projection screen (11). Scanning display of the image slices corresponding to a three-dimensional image is completed when the scatter plates (15) move from the position of one rotating shaft (13) to the position of the other rotating shaft (13). The rotation of the rotating shafts (13) enable a moving screen to move at a constant speed, so that the display effect and service life of the three-dimensional display device (1) can be remarkably improved.