Bone tuberculosis, osteomyelitis and bone tumor with typical X-ray signs are not difficult to diagnose. But those without typical signs may be misdiagnosed. We have misdiagnosed bone tuberculosis as benign bone tumor, osteomyelitis as Ewing's sarcoma and synovial sarcoma, and bone metastasis as bone tuberculosis or osteomyelitis. Looking back and analyzing these misdiagnosed cases, we can find some differences between bone tuberculosis and osteomyelitis and bone tumors: (1) Lesions: flat bone tuberculosis, long tubular bone shaft or osteomyelitis of metaphysis are easily misdiagnosed as tumors, while tumors near joints such as synovial sarcoma are easily misdiagnosed as tuberculosis. When osteolytic lesions are found in these parts, X-ray manifestations should be sought for differential diagnosis. (2) Lesions morphology: ① Lesions with swelling and deformation and clear edges are mostly benign tumors, but they should be differentiated from chondrosarcoma, thyroid cancer metastasis and myeloma. ② Irregular bone destruction and irregular margin should be regarded as the manifestations of malignant tumors, while tuberculosis and erosive suppurative osteomyelitis have regular focus and fuzzy margin, which can be manifested as sclerosis; ③ Periosteal stratification can be seen in tuberculosis, osteomyelitis and Ewing's sarcoma; Triangular periosteal reaction can be seen in osteosarcoma; ④ The joint cavity is narrow, and the bone destruction near the joint is more common in tuberculosis, but it can also be seen in synovial sarcoma. At this time, we should pay attention to whether there is a soft tissue mass.