Multiple myeloma is a malignant tumor with the potential for lung metastasis, a relatively common complication. Multiple myeloma is a malignant disease caused by the abnormal proliferation of myeloma plasma cells. When multiple myeloma progresses to an intermediate to advanced stage, metastasis is rapid and more extensive, and therefore lung metastasis is possible. Metastatic foci can be seen in the lungs on chest CT, either in one or both lobes of the lungs. After the lungs are involved in multiple myeloma, the treatment is mainly systemic therapy for multiple myeloma, and after 4-6 cycles of induction therapy, if the mass in the lungs shrinks significantly, local stereotactic radiotherapy is feasible when there are slight residual foci. If there are still multiple lung metastases, it is necessary to change the chemotherapy regimen or use autologous stem cell transplantation. Specific drugs include bortezomib, cyclophosphamide, and lenalidomide. When lung metastasis occurs in multiple myeloma, it should be treated according to the regimen and standardized treatment under the guidance of doctors to prevent the disease from deteriorating.