The present invention relates to an Nkx3.2 fragment with improved stability under a histopathological environment of arthritis and to a pharmaceutical composition containing the same as an active ingredient. The Nkx3.2 fragment of the present invention has a function to activate NF-κB at the similar level to full-length Nkx3.2 and resistance to proteolysis by Siah1. In addition, the Nkx3.2 fragment exhibited at least a 10-fold improvement in degenerative arthritis treatment effect compared with Nkx3.2 in an animal model-based in vivo efficacy evaluation. Therefore, the Nkx3.2 fragment can be favorably used in the prevention or treatment of arthritis.
