自由立体显示技术是指不需佩戴立体眼镜等附属设备的3维立体显示技术。它可分为全息立体技术、3维集成成像技术、体3维显示技术和基于视差的自由立体显示技术。其中体3维显示技术和基于水平视差的自由立体技术发展很快。本文首先论述了静态体3维显示技术和扫射体3维显示技术两类不同的体3维显示技术近几年来的研究进展；然后从所使用的光学光栅类型及复用方法上综述了基于视差的自由立体显示技术的现状和特点；最后对比了体3维显示技术和基于水平视差的自由立体技术优缺点。

Autostereoscopic display is a kind of three-dimensional technique which need not wear 3D goggles or other equipments. It can be classified into four groups: holography display techniques, integral photography display techniques, volumetric display techniques and horizontal parallax-based autostereoscopic display techniques. In these years, volumetric display techniques and horizontal parallax-based autostereoscopic display techniques develop rapidly. In this paper, we first overview developments in two kinds of volumetric display techniques, which are static volumetric display technique and volumetric display technique based on swept screen, during recent years. Then, make a survey of horizontal parallax-based autostereoscopic display on two ways, the optical sheets used and the multiplex methods. Last, summarize the advantages and disadvantages of volumetric display and autostereoscopic display based on parallax.