Abstract: It is recently discovered that Yi-liang and Yan-jin,the two prefectures in Zhao-tong district of Yunnan,are the most south-western edge of mao bamboo distribution region in Yunnan,China.The writer describes in detail the composition of the bamboo forest and its ecological features including climate,soil and ground vegetation of the new distribution region.He also discusses the major causes of the deficient growth of the bamboo forest in that region,and suggests the necessary measures for better management.