Abstract: The present invention relates to a composition for treating or preventing bone diseases comprising halofuginone as an active ingredient and, more specifically, to a composition for treating or preventing bone diseases, comprising, as an active ingredient, halofuginone having an osteoclast differentiation inhibitory efficacy and an osteoblast differentiation stimulatory activity. The composition for treating or preventing bone diseases, comprising halofuginone as an active ingredient, according to the present invention, reduces the expression of Th17 cells and increases the expression of Treg cells, thereby representing an effect of inhibiting osteoclast differentiation and being capable of also effectively inhibiting bone resorption by osteoclasts. Furthermore, the composition of the present invention will be able to be usefully utilized as a use for the treatment or prevention of bone diseases by being able to promote the differentiation and activity of osteoblast.