Undifferentiated arthritis cannot generally be completely cured, but early stages of undifferentiated arthritis can be relieved by rest, avoidance of mechanical damage to the joints, and physical therapy. There is no uniform clinical definition of undifferentiated arthritis, and the causative factors are not yet fully understood. It is generally accepted that if the joints of the extremities show symptoms of arthritis and the early manifestations of certain connective tissue diseases are excluded, the diagnosis of undifferentiated arthritis can be considered. In the early stages of undifferentiated arthritis, rest, avoidance of mechanical damage to the joints, and physical therapy can relieve muscle tension and reduce pain. Undifferentiated arthritis can be self-limiting or develop into osteoarthritis, rheumatoid arthritis, systemic lupus erythematosus, etc. Some patients still cannot be clearly categorized even after decades of follow-up, or their symptoms remain unchanged for years. In addition, it is recommended that patients with undifferentiated arthritis should have regular reviews to observe their condition, and when discomfort occurs, they should seek prompt medical attention and follow the doctor’s instructions for treatment.