A 3D display device and method using a hybrid position-tracking system is provided, along with a method for displaying the 3D image. The 3D display device includes a main body, a display, a camera, afirst calculation part, a gyroscope, a second calculation part, and a Kalman filter. The display provides a 3D image and the first calculation part calculates a relative posture change of the displaywith respect to a viewing position on the basis of the image photographed by the camera. The gyroscope is mounted in the main body to sense a change in an angular velocity of the display. The second calculation part calculates a relative posture change of the display and the Kalman filter receives the calculation results obtained by the first and second calculation parts to calculate a corrected-posture-change amount of the display.