Multiple myeloma can be asymptomatic in the early stage, and only by chance can we find increased blood sedimentation and abnormal blood immunoglobulins, and as the disease progresses, a series of clinical manifestations can appear, the common ones are as follows: 1) Bone damage: the most common, clinical manifestations are bone pain and bone swelling. x-ray manifestations are: (1) osteolytic lesions, multiple round or oval penetrating changes; (2) diffuse bone (3) pathological fractures; (4) osteosclerosis, often limited, occurring around the osteolytic lesions. A variety of cytokines such as IL-1, IL-6, TNF-β, and osteoclast activating factor are currently thought to be involved in the formation of bone damage. 2, damage to the kidney: due to excessive immunoglobulin light chains filtered by the glomerulus and then reabsorbed in the renal tubules causing tubular damage. Hypercalcemia, hyperuricemia, hyperviscosity syndrome, amyloidosis, tumor infiltration, cytokines (EPO reduction) can aggravate the damage of renal function and renal anemia can occur. Renal impairment is one of the important causes of death for patients. 3, hypercalcemia: mainly for non-ionized calcium increase. Causes of increased blood calcium: (1) abnormal immunoglobulin binding to calcium ions. (2) Release of calcium ions after bone destruction. (3) Resorption of calcium ions by distal renal tubules. 4, hyperviscosity syndrome: due to the large increase of abnormal immunoglobulins in the blood to increase blood viscosity, resulting in impaired blood circulation, mostly seen in IgG type, more easily caused by IgG3 subtype. 5. Amyloidosis: Amyloidosis can occur in about 10-15% of myeloma patients. It may be due to the antigen-antibody reaction resulting in the deposition of protein light chains and polysaccharide complexes in tissues and organs. Peripheral neuropathy and nerve root syndrome: amyloidosis, infiltration of tumor cells, hyperviscosity syndrome, and fracture compression are the main causes of neuropathy, but some patients fail to find the cause of neuropathy.