An autostereoscopic 3D projector using several 2D projectors, a projection screen, and two parallax barriers is proposed. Parallax barrier 1 facing the 2D projectors collimates the images that have aberrations on the edge of the projection screen. Parallax barrier 2 facing viewers acts as the parallax barrier in ordinary autostereoscopic 3D displays. The operation principle of the system, the calculation equations for the parallax barriers, and the capture and correction of parallax images are described in detail. A 60-inch autostereoscopic 3D projector prototype having four 2D projectors was developed. The presentation of 3D static, animation, and video images is realized by the prototype. The prototype's stereoscopic images without aberrations and with a little cross talk are sharp. Especially, its 3D resolution is the same as its 2D resolution.