With the improvement of clinical treatment level of tumor, the primary site of tumor is controlled and the survival period is prolonged, bone metastasis is more and more common. Bone is the third most common site of metastasis besides lung and liver, among which spinal metastasis is common, accounting for about 60%. It is followed by pelvis and long bones of lower limbs, while knee and elbow joints are far less common. Tumors that are prone to bone metastasis from primary cancer are breast cancer, lung cancer, kidney cancer, prostate cancer, rectal cancer, pancreatic cancer, gastric cancer, colon cancer, ovarian cancer and so on. The formation of bone metastases is the result of the interaction between the tumor cells and the host through bloodstream metastasis of the primary cancer, and the more recognized metastasis methods are: 1) the primary tumor cells infiltrate the surrounding tissues and enter the vascular system (blood and lymph); 2) the tumor cells are shed and released into the blood circulation; 3) the tumor cells stay in the blood vessel wall in the bone marrow; 4) the tumor cells escape from the blood vessels through the endothelial cells and then proliferate outside the blood vessels; 5) the metastasis is the result of the establishment of blood transport in the metastases. (5) metastasis is the establishment of blood flow within the cancer lesion, forming a bone metastasis lesion; (6) direct erosion of adjacent tumor tissue. ECT of bone isotope scan is the main means to detect bone metastasis, and X-ray, CT and MRI are also commonly used for the diagnosis of bone metastasis, CT and MRI can not only show bone lesions, but also the surrounding soft tissue lesions and the relationship with adjacent structures. Bone metastases are usually asymptomatic in the early stage, and bone isotope scan can detect the bones with lesions. The symptoms of bone metastases are related to the location and number of tumor metastases, such as bone metastases cause pain with definite pressure points confined to the metastasis site. Spinal cord metastases cause pain in the middle of the posterior back or at the site of the lesion, while bone metastases in the extremities or trunk cause limited pain at that site. Bone metastasis is not a direct cause of life threatening malignant tumor, but if the tumor metastasizes to the weight-bearing bones of the body, such as cervical, thoracic and lumbar vertebrae, it can cause serious consequences of paralysis. Therefore, patients with bone metastases should be treated promptly. For patients with bone metastases, the treatment of local tumor is palliative treatment, and the basic goal is to prolong the survival time and improve the quality of life of patients. Therefore, comprehensive treatment combined with local treatment is required. (1) Surgery The purpose of surgical treatment for metastatic bone tumors is to reduce patients’ pain, prevent the occurrence of pathological fractures, restore or preserve limb functions, and facilitate further treatment and care. At the same time, it improves the psychological tolerance of patients and the quality of their survival with tumor. Selecting appropriate surgical indications and moderate surgery have positive significance for patients with bone metastasis cancer. The primary tumors causing bone metastases are complex and diverse, and the selection of surgical treatment for patients with bone metastases must be individualized and fully consider the patients’ systemic and local conditions and expectations for treatment as well as the diagnosis and treatment of primary cancer, whether they are sensitive to the efficacy of chemotherapy, radiotherapy and biological treatment, and understand the prognosis of primary cancer. (2) Chemotherapy Chemotherapy, especially high-dose standardized chemotherapy, enables about 80/~85% of patients with primary malignant bone tumors to undergo limb-preserving treatment, and the 5-year survival rate is increased to more than 80%. Patients with metastatic bone tumors are mostly in advanced stages of cancer, and combination chemotherapy is superior to single agent chemotherapy in terms of remission rate and survival, and is also suitable for patients with poor general status. The choice of chemotherapy drugs is mainly based on the cytological nature of the primary focus. (3) Radiation therapy, including external radiation and brachytherapy, is an important method for treating many malignant bone tumors that are sensitive to radiotherapy, and the main purposes of radiation therapy [18,19]: (1) local treatment of tumors and direct killing of tumor cells; (2) pain relief and prevention of pathological fractures; (3) reduction of tumors for surgical resection; (4) radiation therapy after palliative resection of tumors. 125I (iodine-125), etc. Inter-tissue implantation brachytherapy with radioactive particles of medium half-life and low energy radiation has emerged in recent years and can be used not only for single lesion treatment, but also for multiple bone metastases. Particle implantation brachytherapy has shown the advantages of high efficacy, low side effects and short treatment period. (4) Interventional treatment Percutaneous vertebroplasty (PVP), in which bone cement is injected into the vertebral body to relieve pain and prevent vertebral collapse, is indicated for invasive vertebral hemangioma and inoperable vertebral osteolytic tumors causing decreased spinal stability and posterior back pain. Interventional chemotherapy has become an effective treatment option, and arterial interventional chemotherapy can increase local drug concentrations and reduce toxic side effects. If the vascular anatomy is well understood, embolization of the thickened and tumor-stained target vessels should be performed as much as possible. (5) Endocrine therapy Some hormone-dependent tumors are effective for endocrine therapy, such as hormone receptor-positive breast cancer and prostate cancer bone metastases, and endocrine therapy is especially important. Patients with endocrine therapy should be reviewed on a monthly basis and can be treated with drugs until the disease progresses. Calcitonin can prevent bone calcium loss and increase bone mass, and also has a central analgesic effect, thus controlling bone pain. (6) Bisphosphonates Bisphosphonate chemotherapy has become a well-established treatment option for bone metastatic tumors, which can inhibit osteolysis, relieve pain, and reduce and delay the occurrence of bone-related complications of metastases. The toxic side effects of bisphosphonates are mainly nephrotoxicity. (7) Radionuclide therapy Radionuclide drugs such as 89 strontium (89Sr), 153 samarium (153Sm) and 32 phosphorus (32P) have low adverse effects and high pain relief rate. They are mainly used for prostate cancer, breast cancer and other osteogenic bone metastases, and also have good efficacy in patients with recurrence after external radiotherapy. (8) Narcotic analgesic drug therapy The WHO guidelines for three-step treatment of cancer pain are now considered to be the standard protocol for controlling advanced cancer pain. For patients with metastatic bone tumor, most of them have persistent moderate or severe pain and often need to use opioid analgesics, which can rapidly relieve pain. (9) Other treatments: Physiotherapy that has been proved to be effective, such as HIFU, RFA, microwave, freezing, etc., can also be used as local treatment for bone tumors. Immunotherapy, inhibition of tumor angiogenesis and gene therapy are also being explored.