Swelling of fingers after sleeping is usually caused by tenosynovitis, synovitis, occupational lesions and microcirculation disorders. 1. Tenosynovitis: morning stiffness caused by tenosynovitis occurs when the hand is swollen after sleeping, sometimes combined with symptoms such as stiffness or pain in the hand. It is usually caused by edema, hyperplasia and compression of tendons in the tendon sheaths, and is mostly related to frequent activities or exertion of the hands. 2. Synovitis: Synovial hyperplasia and edema may be caused by age-related synovial degeneration or specific synovitis, such as rheumatoid synovitis. 3. Position-occupying lesions: such as cysts or tenosynovial giant cell tumor in the tendon sheath, which occupies the space, thus affecting the normal movement of the hand and joints, and the joints may be swollen when waking up in the morning. 4. Microcirculation disorders: such as vascular diseases, especially those with poor peripheral circulation, such as Raynaud’s syndrome with spasms after exposure to cold, or may be poor peripheral circulation, such as diabetes, peripheral nerve and blood vessel dystrophy caused by the swelling. When the swelling of the fingers is found after sleeping and not relieved for a long time, it is necessary to consult a doctor for examination and treatment of the cause.