Abstract: This paper deals with the geographical position, geological and paleogeographical environment, habitat, species composition and relationship of two natural cycad communities from China, i.e. Cycas taitungensis community in Taiwan, and Cycas panzhihuaensis community in Sichuan. We think that: 1.The two communities are located distantly in east and west parts of China. Though they are located in subtropical evergreen broad-leaved foreet region of China, they belong to east moist and west dry subregion, respectively. The majority of the species composition of the former community is of Sino-Japanese elements, indicating close relationehip with southeast coast region of mainland China. Accordingly it is presumed that C. taitungensis and C. taiwaniana from Guangdong, C. hainanensis, and C. guizhouensis form geographical species in a species group. While the species in C. panzhihuaensis community floristically consist of mainly Sino-Himalayan elements, with earlier origin. These two communities have common origin but differentiated in separate natural conditions. 2. Geomorphologically the mountains in the two places are north-south orientated, and are advantageous to the migration and conservation of plants during glaciation time. 3. These two communities are of secondary origin. With similar habitat of stony and barren soil. Their similarities are possibly the dependence of relic plants on unfavourable habitat in struggle for existence.