A 3D display apparatus is provided, which comprises: a display, a camera configured to track human-eye position information of human eyes, and a processor electrically connected with the camera and configured to generate a control signal according to the human-eye position information. Preferably, the display comprises a dynamic grating, which is electrically connected with the processor and configured to, according to the control signal, control bright and dark stripes of the dynamic grating to change in position adaptively according to positions of human eyes. Thereby, the 3D display apparatus of the present disclosure utilizes the camera to track human-eye position information and then utilizes the control unit to change positions of bright and dark stripes of the grating according to the human-eye position information so as to adapt to different observing positions of the user's two eyes, thus achieving a 3D image effect.