A composition for promoting longitudinal bone growth, according to the present invention, promotes the proliferation of the chondrocytes and the differentiation of the osteoblasts and has effects of simultaneously increasing longitudinal bone length and thickness (bone density), and thus has an advantage of being widely prescribable to various age groups, thereby being usable as a pharmaceutical composition for promoting the growth of longitudinal bone length and thickness. An indirubin derivative according to the present invention has prevention or treatment effects through oral administration and has an excellent competitive price unlike conventional hormone-based therapeutic agents. In addition, unlike conventional therapeutic agents, the pharmaceutical composition for preventing or treating bone diseases of the present invention is a stable compound, which is known to be substantially noncytotoxic to the human body, and is a material of which adverse effects have not been identified and which has excellent treatment effects for bone diseases and osteogenesis imperfecta.
