Objective To explore the laboratory characteristics of multiple myeloma（MM）complicated with renal injury，and evaluate the effectiveness of diagnosis combined with multiple index. Methods The clinical data from 157 patients with MM including 30 complicated with renal injury and 127 without renal injury who had been treated from June 2018 to March 2021 in the department of Hematology，Nanfang Hospital and General Hospital of the Southern Theater of the Chinese People′s Liberation Army were retrospectively analyzed. The laboratory results were compared，the risk factors complicated with renal injury were analyzed，and the diagnostic efficiency of single detection was compared with that of combined detection in MM complicated with renal injury. Results Levels of urea nitrogen，uric acid，β2⁃microglobulin，and calcium⁃calibration，and ratio of neutrophil/lymphocyte （NLR）were higher in MM patients complicated by renal injury than in those without renal injury（P < 0.05）. An increase in calcium⁃calibration，β2⁃microglobulin or NLR were the independent risk factors for MM with renal inju⁃ ry. The combined detection of β2⁃microglobulin，calcium⁃calibration and NLR has higher sensitivity and specifici⁃ ty. Conclusions Calcium⁃calibration，β2⁃microglobulin and NLR were independent risk factors for MM with re⁃ nal injury and have better predictive value.