The criteria for early diagnosis of osteomyelitis are mainly based on clinical manifestations, physical examination, laboratory examination and imaging examination. 1. Clinical manifestations: systemic symptoms such as chills, high fever and other symptoms of toxemia, and severe pain in the metaphysis of long bones. 2. Physical examination: deep pressure and pain in the epiphysis of the long bones, limitation of movement, local redness and swelling. 3. Laboratory examination: blood leukocyte count and neutrophilia, local puncture to extract pus and culture bacteria are the gold standard for the diagnosis of septic osteomyelitis. 4. Imaging examination: it is difficult to find obvious changes in X-ray in the early stage, but magnetic resonance can show the inflammatory reaction of bone and subperiosteum, with or without abscess formation, which has early diagnostic value. Osteomyelitis is difficult to be cured if it develops to the late stage, so it is recommended that patients should consult the hospital in time for timely treatment to avoid adverse consequences.