There is no simple way to determine osteosarcoma in clinical practice, and it should be judged comprehensively through physical examination, laboratory examination, imaging examination and pathological examination under the guidance of doctors. 1. Physician’s examination: during the examination, it is necessary to determine whether there are local lumps, local pressure and pain, etc. It is also necessary to compare the skin temperature and determine whether there is swelling, and to examine whether there are pathologic fracture and joint hypermobility. 2. Laboratory examination: if the presence of osteosarcoma is suspected, lactate dehydrogenase and plasma alkaline phosphatase should be detected according to the doctor’s prescription. 3. Imaging examination: X-ray examination should be carried out in time to detect the presence of periosteal reaction, bone destruction and irregular new bone. CT examination is also needed to detect bone destruction and the degree of mineralization within the tumor. Magnetic resonance imaging is also needed to check the extent of soft tissue invasion by osteosarcoma. It is also paired with an isotope bone scan, which may show radio-concentration and can also be used to determine the localization and characterization of the osteosarcoma. Early diagnosis and differential diagnosis of the tumor should also be carried out by means of positron emission computed tomography. 4. Pathological examination: Usually, biopsy should be carried out through puncture or incision, and its classification should be clarified through pathological examination, so as to reasonably guide the subsequent treatment. When abnormal phenomenon occurs, the osteosarcoma should be judged rationally under the guidance of doctors and treated in time.