The present invention relates to a composition for articular cavity injection comprising a nucleic acid and chitosan. More specifically, in the present invention, it was confirmed that the sol-gel transition occurred depending on the temperature in the composition for articular cavity injection prepared through the mixing of the nucleic acid and chitosan, the proteoglycan biosynthesis of the cartilage tissue was increased by the injection of the composition and the cartilage regeneration effect was exhibited, and the pain was alleviated and the walking speed and stride which are the joint motilities were improved. Therefore, development of a therapeutic agent for arthritis having an excellent therapeutic effect using the composition for articular cavity injection comprising the nucleic acid and chitosan of the present invention is expected.
