Multiple myeloma is a malignant proliferative disease of plasma cells, and some patients may develop systemic amyloidosis. Cardiac amyloidosis is a common cause of death in these patients. Secondary adrenal insufficiency is caused by dysfunction of the hypothalamus and/or the pituitary gland, and multiple myeloma cases combined with secondary adrenal cortical dysfunction have been rarely reported in China. The patient, 55-year-old, male, was admitted to the Emergency Department of Shenzhen Luohu People's Hospital on June 5, 2018 due to "repeated chest tightness and fatigue for 7 months, and fainting for 1 hour". Later, he was transferred to Department of Hematology and was diagnosed as having multiple myeloma (λ light chain type) with systemic amyloidosis through bone marrow puncture and other examinations. The first course regimen of chemotherapy was bortezomib, cyclophosphamide, and dexamethasone. After the course, the patient was infected with a mixture of bacteria and fungi in the lung and had improvement after treatment. Then the regimen was adjusted to bortezomib and dexamethasone from the second course. After the fourth course, the patient achieved complete remission of multiple myeloma. After the fifth course, the patient experienced severe pulmonary-mixed infection again, which was improved after treatment. Thereafter, the patient presented with refractory hypotension, and decreased levels of cortisol and adrenocorticotropic hormone (ACTH), which was diagnosed as secondary adrenal cortical dysfunction. Hydrocortisone replacement therapy was administered. After 9 courses of chemotherapy, the patient received maintenance treatment with ixazomib. Multiple myeloma was evaluated as a stringent complete response. Cardiac amyloidosis was evaluated as a very good partial response, and secondary adrenal cortical dysfunction was treated with hydrocortisone maintenance therapy and with the cortisol level in the normal range.