The number of Yi language ancient books is large, but it's in rapidly reduced, the need to use the scientific method to rescue, organize, specification. To meet the needs of archaeologists and publishing industry, from practicability consideration of Chinese, English, Yi language mixed input in the composing system, using Unicode international coding standard, and realizing the character encoding range from the self-created interval to Chinese interval across. This paper expouned the South Yunnan Yi font design and input method realization involved principles and many issues based on Windows operating systems, and on this basis, use Duoduo-input method API for application development, after overcoming technical obstacles such as the operating system application environments, the font encoding interval and mode, text mixed display, Finally developed the "southern Yunnan Yi digital information processing platform". Whether it is from the analysis of feasibility and practicality on this platform, the third style "Southern Yunnan Yi language free split mode one-to-many shape code input method" to solve learnability problem of the current Yi character input method. it's a stable operation, enter quick, easy learning Yi input method, especially for the promotion of Yi language information technology has widely value in use and application.