Firstly the extension nature of matter-element concepts is analyzed simply in this paper. According to matter-element theory, the vulnerability of landslide hazard in Hunan Province is used as a typical example, and at the same time, the vulnerability of landslide is of divergence, extension, interrelation and conjugation, which are typical characters of matter-element model. Based on these special characters, the author proposed that extension should be used in the vulnerability of landslide hazard reduction besides the traditional ways.