Abstract： Objective To investigate the value of bone marrow smear combined with CRP and LDH indicators for the di-agnosis and disease assessment of MM.Methods 72 patients diagnosed with MM,and 30 patients who underwent bone marrow aspiration for other reasons were selected as the control group during the same period,compared the differences in bone marrow smears and other differences between the 2 groups.Results The percentage of bone marrow plasma cells and serum LDH and CRP levels in the study group were significantly higher than those in the control group(P＜0.05);The percentage of bone marrow plasma cells and serum LDH and CRP levels in the control group,MM stage I,MM stage Ⅱ and MM stage Ⅲ patients gradually increased(P＜0.05);The serum LDH and CRP levels were higher in patients with primitive and naive plasma cell types than in mature plasma cell types,respectively(P＜0.05);ROC curve analysis:the combination of bone marrow smear,serum LDH and CRP levels was the largest in diagnosing MM AUC(0.913),with good diagnostic efficacy and best sensitivity and specificity of 91.6％and 85.6％,respectively.Conclusion The combined diagnosis of MM with bone marrow smear,serum LDH and CRP levels is of greater value and helps to improve the sensitivity and accuracy of the diagnosis of this disease.