Abstract: Avatar technique is important to applications such as virtual environments，simulation and digital entertainment.This paper first reviews the history and definition of avatar.Then it surveys relevant techniques such as human body modeling，real-time rendering，character animation and affection computation by introducing，comparing and summarizing representative algorithms.After the introduction of several typical applications，it is concluded with the direction of future research.

Key words: virtual environments, avatar, human body modeling, character animation, affection computation

摘要： 化身（Avatar）是虚拟环境、系统仿真和数字娱乐等应用中的一项重要技术。首先回顾用户化身的发展历史和定义，然后综述其中的人体建模、实时绘制、角色动画和情感计算等基本技术，介绍代表性算法，并加以比较和总结。在介绍几种典型的应用之后，指出未来的发展方向。

关键词: 虚拟环境, 化身, 人体建模, 角色动画, 情感计算