Bone cancer is a malignant bone tumor that occurs in the bone or its appendages, which is divided into primary and secondary, with rapid development, poor prognosis and high mortality. The etiology of bone tumor is complex and still unknown, there are several theories as follows: 1. Genetic theory: genetic mutation can cause tumor, people with history of bone tumor in first-degree relatives are more prone to the disease, so regular examination is needed to check the disease. 2.Stimulation theory: Physical factors such as ionizing radiation, excessive exposure to ultraviolet light, environmental pollution, ionizing radiation, fractures, burns and other injuries can induce the occurrence of malignant bone tumors. 3.Biological theory: viruses, bacteria, fungi, parasites, etc. change the sequencing of genes, which leads to the occurrence of bone tumors. For example, infectious synovitis caused by less virulent bacteria may be related to the occurrence of synovial tumor. 4. Other factors: immune factors, endocrine factors, psychosocial factors, etc., such as growth hormone can stimulate the occurrence of malignant bone tumor, and malignant bone tumor in adolescents grows rapidly and metastasis can occur in early stage. In conclusion, the etiology of bone tumor is complex, so it is necessary to actively eliminate or reduce cancer-causing risk factors, reduce exposure to harmful factors in the environment, achieve primary prevention, early diagnosis and early treatment to reduce the incidence of bone tumor.