Heptacodium miconioides Rehd. (Caprifoliaceae), seven-son-flower, is an endangered species endemic to China. The population structure of H. miconioides was analyzed at genet and ramet levels, respectively, in Dapan Mountain of Zhejiang Province. No individual of size class I (height0.33m) was found in all studied sites. Size-class III and IV had most abundant individuals. At ramet level, size-class II and III had most abundant stems. Generally, size-class structure indicated a relatively stable situation in Dapan Mountain. However, in some sites, H. miconioides had the risk of local extinction. Sites at mid-altitude had lowest stems per individual, whereas more stems per individual were found at lower or higher sites. Individuals of the largest size class (size class V) had significant more stems per individual than size class III and critically significant more than size class IV. Our observation indicated that the population of Dapan Mountain was regenerated via asexual reproduction. These results showed that H. miconioides in Dapan Mountain could be maintained if no dramatic changes in the habitats. A reserve should be set because Dapan Mountain may be the largest population of H. miconioides.