Both are rheumatic diseases. About 80% of patients with SLE have joint pain and swelling, and the most vulnerable joints are the proximal interphalangeal joints, knees, wrists, and metacarpophalangeal joints. About half of the patients have mild, short-lived morning stiffness and rarely have joint deformities, but there are no erosive joint changes or bone changes on X-ray. Patients are mostly female, with facial erythema and visceral damage, and most have renal damage and proteinuria. Raynaud’s phenomenon is common, while subcutaneous nodules are rare and serum anti-DNA antibodies are significantly elevated. Osteoarthritis is a degenerative joint disease. The onset of the disease is mostly above 45 years of age, increasing with age, and is more common in the elderly, with no gender differences. The distal interphalangeal joints and weight-bearing joints (knees and hips) are the most commonly affected joints. Soft tissue swelling is rare and there are no rheumatoid nodules, but Heberden’s nodules can be seen in the distal interphalangeal joints. In the proximal interphalangeal joints, joint involvement may be asymmetric; normal blood sedimentation, negative rheumatoid factor, joint x-ray shows narrowing of the joint space, subchondral bone sclerosis, elephantiasis, marginal bone redundancy and cystic lesions, no erosive lesions.