Abstract: The investigation of forest in Yunnan Province for nearly half a century was carried out, and the relevant academic literature were reviewed, compared and verified. Based on the situation of forest in Yunnan, the classification system of community types of natural forest in Yunnan was established by using the principles, units and systems of forest classification in China. The findings indicated that Yunnan natural forest system is divided into 4 forest classes groups, 16 forest classes, 328 forest formations and several forest types. The introduction of Yunnan′s geographical environment and the forestation reason is helpful to clarify the diversity, complexity, uniqueness of geographic distribution, and its systematic characteristics of forest types in Yunnan.