Abstract: Based on Braun - Blanquet' s syntaxa of phytosociological or floristic- sociological classification methods, the classification system table of Class-Order -Alliance -Association of the dry- hot valley vegetation in Yunnan- Sichuan region has been established. In this system table, there are 1 Class, 4 Orders, 10 Alliances and 64 Assciations in the semi - savanna vegetation of valley type of 3 Rivers (Yuanjiang, Nujiang, Jin-shajiang), sorted out from 523 releves. This system table is a simple form, it is made from 3 synoptic - syntaxon table (Class table) each for 3 Rivers. The system table reflects the diversity, characeristics and unique structure of every syntaxa and their floristic component, especially character species of the dry - hot vegetation in Yunnan- Sichuan region.

Key words: Yunnnan - Sichuan region