This study was purposed to investigate the expressions of miR-21, miR-155 and miR-210 in plasma of patients with lymphoma, and explore their role played in diagnosis, evaluation of chemotherapy effect and prognosis of lymphoma. The expressions of miR-21, miR-155 and miR-210 were assayed by RT-PCR in plasma of 54 cases of lymphoma, 10 cases of lymphonode inflammation and 27 cases of normal controls. The results indicated that the expressions of miR-21, miR-155 and miR-210 in plasma of lymphoma patients were higher than those of control group and lymphonode inflammation group (P < 0.05). The expressions of miR-21 and miR-210 in plasma of control group and lymphonode inflammation group had no significant differences (P > 0.05). The expression of miR-21 in plasma of lymphoma patient group significantly correlated with their serum LDH level. The expressions of miR-21 and miR-210 in plasma of previously untreated lymphoma patient group were higher than those of the patients treated for 6 or more courses (P < 0.05). The diagnostic accuracy of miR-21, miR-155 and miR-210 used for lymphoma patients was 56, 65, 48 respectively, and reached to 83 when combined three of them. It is concluded that the expressions of miR-21, miR-155 and miR-210 in plasma of lymphoma patients were significantly higher. Detection of these 3 miRNA in plasma of patients can contribute to the clinical diagnosis, treatment and prognosis evaluation of lymphoma.