ObjectiveTo observe the changes of peripheral blood lymphocyte subsets of patients with primary hepatocellular carcinoma (PHCC) treated with radiofrequency ablation (RFA). MethodsThe data of 70 cases of hospitalized patients with PHCC that voluntary accepted RFA diagnosed by clinical and pathological in our hospital between July 2011 and December 2014 were collected. According to the numbers of HCC lesions, 70 cases were divided into single focus group (n=41) and multifocal group (n=29). The changes of their immune parameters before and after RFA were analyzed. Results①The ratioes of peripheral blood CD3+/CD19-, CD3+/CD4+, CD4+/CD8+, and NK cells on 7 days and 14 days after RFA treatment of 70 cases were significantly higher than those on 1 day before RFA treatment (P < 0.05). The ratio of CD3+/CD8+ T cells reduced from 1 day before RFA treatment to 14 days after RFA treatment, but the difference was no statistically significant (P > 0.05).②The changing trend of peripheral blood lymphocyte subsets before and after RFA treatment in single focus group and multifocal group were similar to the above.③Compared with single focus group, the ratioes of peripheral blood CD3+/CD19-, CD3+/CD4+, CD4+/CD8+, and NK cells before and after RFA treatment in multifocal group were lower, and the ratio of CD3+/CD8+ T cells was higher, but the difference were not statistically significant (P > 0.05). ConclusionRFA can not only destroy small PHCC foci, but also to significantly improve immune function and enhance the anti-tumor effect.