ISO/IEC 10646:2003规定了通用多八位字节编码字符集(UCS)。它适用于世界语言的书面形式以及附加符号的表示、传输、交换、处理、存储、输入和呈现。 ISO/IEC 10646:2003 规定了ISO/IEC 10646:2003的体系结构；定义ISO/IEC 10646:2003中使用的术语；描述编码字符集的一般结构；指定UCS的基本多语言平面（BMP）；指定UCS的补充平面:补充多语言平面（SMP）、补充表意文字平面（SIP）和补充特殊用途平面（SSP）；定义了一组在世界范围内用于脚本和语言书面形式的图形字符；指定BMP、SMP、SIP、SSP的图形字符的名称及其编码表示；指定UCS的四个八位字节（32位）规范形式:UCS-4；指定UCS的两个八位字节（16位）BMP形式:UCS-2；指定用于ISO 646(ASCII)面向字节的环境的多字节（一到四个）字节转换UTF-8；为补充字符指定两个16位形式和相关的转换UTF-16；指定所选字符集子集的集合标识符；指定控制函数的编码表示；指定对此编码字符集的未来添加的管理；通过引用结合了Unicode双向算法和规范化形式。 UCS是一种不同于ISO/IEC 2022中规定的编码系统。在ISO/IEC 10646:2003中，图形字符将仅分配一个代码位置，位于BMP或其中一个补充平面中。注意-Unicode标准4.0版包括一组与ISO/IEC 10646:2003中相同的字符、名称和编码表示。此外，它还提供了对实施者有用的字符属性、处理算法和定义的细节。4.0版加强了Unicode对全球通信、软件可用性和发布的支持。 通过定义编码多语言文本的一致方式，ISO/IEC 10646:2003实现了国际数据交换。信息技术行业获得了数据稳定性、更大的全球互操作性和数据交换。ISO/IEC 10646:2003已经在新的互联网和W3C协议以及XML和HTML等标记语言中广泛采用，并在现代操作系统和计算机编程语言中实现。这个版本涵盖了世界上超过96 000个剧本中的角色。

ISO/IEC 10646:2003 specifies the Universal Multiple-Octet Coded Character Set (UCS). It is applicable to the representation, transmission, interchange, processing, storage, input and presentation of the written form of the languages of the world as well as additional symbols. ISO/IEC 10646:2003

• specifies the architecture of ISO/IEC 10646:2003;
• defines terms used in ISO/IEC 10646:2003;
• describes the general structure of the coded character set;
• specifies the Basic Multilingual Plane (BMP) of the UCS;
• specifies supplementary planes of the UCS: the Supplementary Multilingual Plane (SMP), the Supplementary Ideographic Plane (SIP) and the Supplementary Special-purpose Plane (SSP);
• defines a set of graphic characters used in scripts and the written form of languages on a world-wide scale;
• specifies the names for the graphic characters of the BMP, SMP, SIP, SSP and their coded representations;
• specifies the four-octet (32-bit) canonical form of the UCS: UCS-4;
• specifies a two-octet (16-bit) BMP form of the UCS: UCS-2;
• specifies a multiple byte (one to four) byte transformation UTF-8 for use with ISO 646 (ASCII) byte-oriented environments;
• specifies a two 16-bit form and associated transformation UTF-16 for supplementary characters;
• specifies collection identifiers for selected set of character subsets;
• specifies the coded representations for control functions;
• specifies the management of future additions to this coded character set;
• incorporates the Unicode bi-directional algorithm and normalization forms by reference.

The UCS is a coding system different from that specified in ISO/IEC 2022. A graphic character will be assigned only one code position in ISO/IEC 10646:2003, located either in the BMP or in one of the supplementary planes. NOTE - The Unicode Standard, Version 4.0 includes a set of characters, names, and coded representations that are identical with those in ISO/IEC 10646:2003. It additionally provides details of character properties, processing algorithms, and definitions that are useful to implementers. Version 4.0 strengthens Unicode support for worldwide communication, software availability, and publishing. By defining a consistent way of encoding multilingual text ISO/IEC 10646:2003 enables the exchange of data internationally. The information technology industry gains data stability, greater global interoperability and data interchange. ISO/IEC 10646:2003 has been widely adopted in new Internet and W3C protocols and mark up languages such as XML and HTML, and implemented in modern operating systems and computer programming languages. This edition covers over 96 000 characters from the world's scripts.