Objective To analyze the clinical features of patients with multiple myeloma (MM) complicated with renal function damage and prognostic factors of patients. Methods The related data of 206 patients with MM complicated with renal function damage treated in our hospital from May 2015 to May 2017 were retrospectively analyzed. Clinical features and prognosis of patients were analyzed. Factors related to the prognosis were analyzed by univariate and multivariate Logistic regression analyses. Results There were 108 cases (52.43%) with cast nephropathy, 68 cases (33.01%) with amyloidosis and 30 cases (14.56%) with other lesions. The main DS stages of patients with cast nephropathy, patients with amyloidosis and patients with other lesions were stage Ⅲ, stage Ⅰ and stage Ⅲ, respectively (P＜0.05). The hemoglobin level in patients with amyloidosis was significantly higher than that in the other two groups (P＜0.05). The serum albumin levels and ratio of bone marrow plasma cells ranking from high to low was as follows: cast nephropathy, other lesions and amyloidosis. 24h proteinuria ranking from high to low was as follows: amyloidosis, cast nephropathy and other lesions. There were significant differences among the three groups (P＜0.05). The serum creatinine level in patients with cast nephropathy was significantly higher than that in the other two groups (P＜0.05). The main type of immunoglobulin detected in patients with cast nephropathy was nonporous type, while immunoglobulins detected in patients with amyloidosis and other types of lesions mainly were IgG type (P＜0.05). The monoclonal light chain of the three groups mainly was λ type. 8 of the 206 patients were lost to followup during the followup period. The 2year cumulative survival rate of 202 patients was 891%. The 2year cumulative survival rates of patients with tubular nephropathy, amyloidosis and other types of lesions were 877%, 910% and 89.7%, respectively. White blood cell count, hemoglobin, serum albumin, percentage of bone marrow plasma cells, blood β2microglobulin, platelets, DS staging and ECOG score were related to the prognosis of patients (P＜0.05). There was no correlation between gender, age, 24h proteinuria, serum creatinine and serum calcium level (P＞0.05). Multivariate Logistic regression analysis showed that the blood β2microglobulin level, ECOG score, increased proportion of bone marrow plasma cells, decreased serum albumin level and DS staging were risk factors for poor prognosis (P＜0.05). Conclusion The main renal lesion in patients with MM complicated with renal function damage is cast nephropathy. The main type of monoclonal light chain is λ type. Elevated blood β2microglobulin level, ECOG score and the proportion of bone marrow plasma cells and decreased serum albumin levels and DS staging are risk factors for poor prognosis of patients.