Abstract: To investigate the regulatory effects of purple sweet potato anthocyanins(PSPA),preparation of mice splenic lymphocytes,the effect of PSPA on lymphocyte was detected with MTT assay. The cell membrane surface marker and cell cycle of PSPA on splenic lymphocyte was detected by flow cytometry. The results showed that lymphocyte stimulation index of all concentration PSPA group(p<0.01)was extremely significantly higher than the blank control group(p<0.01),the lymphocyte stimulation index of 20 mg/mL PSPA group was extremely significantly higher than positive control group(p<0.01). The CD4⁺/CD8⁺ ratio of lymphocyte subsets of 2.5 mg/mL PSPA group was significantly higher than blank control group(p<0.05),the CD4+/CD8+ratio of lymphocyte subsets of 5,10 and 20 mg/mL PSPA group was extremely significantly higher than blank control group(p<0.01). The CD4⁺ CD8⁺ percentage of lymphocyte subsets was extremely significantly higher 2.0 mg/mL PSPA group than positive control group(p<0.01). The percentage of lymphocytes in the S phase of all concentration PSPA group was extremely significantly higher than the blank control group(p<0.01). The percentage of lymphocytes in the S phase of 20 mg/mL concentration PSPA group was extremely significantly higher than positive control group(p<0.01). It was Indicated that PSPA can promoted lymphocyte proliferation,increased CD4⁺/CD8⁺ subgroup ratio,increased the percentage of cells in the S phase,thereby regulated the immune function of lymphocytes. Conclusion:PSPA has obvious immunomodulatory activity.