Bone tumors can be classified as benign and malignant, but there is sometimes no clear-cut line between them, and even both benign and malignant histological features can exist in the same tumor. The following are the conditions that should be noted for early detection of bone tumor? The occurrence of malignant bone tumor is related to the vigorous growth of bones, most of them occur in the age of 10-30 years old, and 10-20 years old is the peak of incidence. Adolescent patients should be highly alert when they feel pain and swelling (or lump) of limbs in the same location, with fixed and persistent characteristics, especially at night, and getting worse day by day. When you feel that the pain and swelling of the limbs are not caused by trauma, inflammation or wind-cold, you must not take it lightly and go for further examination. 2. In case of acute osteomyelitis such as fever, limb pain, swelling and leukocytosis in adolescents, the possibility of Ewing’s sarcoma and osteosarcoma should be excluded. 3.When the original benign lump on the bone suddenly increases in size and is accompanied by pain, it indicates a possible trend of malignancy. Multiple endophytic chondrosarcomas, multiple osteochondrosarcomas and long tubular solitary osteochondrosarcomas are all prone to malignant transformation into chondrosarcoma, and should be reviewed regularly to prevent malignant transformation. 4.If the elderly have unexplained limb pain and low back pain, and there is a tendency of progressive aggravation, they should be alert to the possibility of metastatic bone tumor. 5.When there is swelling, local mass, pain in the soft tissue of the limbs and pressure pain in the tendon membrane, fascia and adjacent parts of the joints, the possibility of synovial sarcoma should be considered first, and it should not be easily explained by benign lesions such as arthritis, cysts and fibroids. 6.Patients with no obvious abnormalities in X-ray examination and other manifestations, but the progress of disease is not consistent with trauma or benign lesions, should pay attention to strengthen local observation and regular review or consult doctors with expertise in bone tumor for further examination. 7.For early detection of bone tumor, patients with the above conditions and highly suspected malignant bone tumor should undergo X-ray examination, radioisotope bone scan, CT examination, MRI examination, puncture or incisional pathological biopsy to clarify the diagnosis.