Two types of complex text layout engine are widely used today: one is Microsoft’s Uniscribe and the other is IBM’s ICU. By studying on its mechanism and analyzing the source code of a certain type of open source complex layout engine (such as ICU layout engine), we can add new code models which support new complex scripts (such as China’s minority language Mongolian, Tibetan, and Uigur) into the complex text layout engine and develop a version of office software based on OpenOffice for China’s minority. This paper firstly explains what the complex scripts and complex text are; then it analyzes the mechanism of the complex text layout engine; lastly it illustrates how to apply the complex layout engine to develop a version of office software based on OpenOffice suitable for China’s minority.