Whether a kidney puncture report showing negative Congo red is myeloma nephropathy needs to be determined by the type of pathology. Light chain type amyloidosis Congo red stains positive in myeloma nephropathy while light chain deposition disease Congo red stains negative. Multiple myeloma is a malignant disease with an abnormal proliferation of plasma cell lineages, often causing different types of renal damage. It is mainly seen in tubulointerstitial lesions and glomerular lesions, and glomerular lesions are mainly seen in light-chain amyloidosis and light-chain deposition disease. Light-chain amyloidosis is characterized by the deposition of large amounts of structureless eosinophilic homogeneous amyloid in various parts of the kidney, and the amyloid stains positively with Congo red, while light-chain depositional disease is characterized by thickening of the thylakoid membranes and widening of the stroma, and the staining is negative with Congo red. Therefore, Congo red negative may also be myeloma nephropathy. Patients who are considered to have myeloma nephropathy are recommended to go to regular hospitals for timely consultation and standardized treatment under the guidance of doctors.