Objective: To explore the significance of lymphocytes in systemic sclerosis (SSc), by detecting the levels of T lymphocytes, B lymphocytes and natural killer (NK) cells, and analyzing the correlation between the lymphocytes and clinical laboratory indexes. Methods: The numbers and proportion of T, CD4⁺T, CD8⁺T, B, and NK cells were detected by flow cytometry in peripheral blood of 32 SSc patients who had taken immunosuppressive drugs and 30 healthy controls (HC). The comparison of the lymphocyte subsets in SSc with them in the HC groups, and the correlation between the lymphocytes and other clinical and laboratory indicators were analyzed by the relevant statistical analysis. Results: Compared with the HC group, the numbers of T, CD4⁺T, CD8⁺T, and NK cells in peripheral blood of SSc group,who had taken immunosuppressive drugs, were significantly decreased (P<0.05). More-over, the proportion of NK cells in peripheral blood of the SSc group was also significantly lower than that in the HC group (P=0.004). In addition, all the lymphocyte subsets were decreased in peripheral blood of more than 65% of the SSc patients who had taken immunosuppressive drugs. Compared with CD4⁺T normal group, the positivity of Raynaud’s phenomenon, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) was significantly increased in CD4⁺T reduction group, respectively (P=0.024, P<0.001, P=0.018). ESR was higher in CD8⁺T reduction group than CD8⁺T normal group (P=0.022). The prevalence of fingertip ulcer was significantly increased in B cell decrease group (P=0.019). Compared with NK cell normal group, the prevalence of fingertip ulcer was significantly increased in NK cell lower group (P=0.033), IgM was remarkablely decreased yet (P=0.049). The correlation analysis showed that ESR was negatively correlated with the counts of T lymphocytes (r=-0.455, P=0.009), CD4⁺T lymphocytes (r=-0.416, P=0.018), CD8⁺T lymphocytes (r=-0.430, P=0.014), B cells (r=-0.366, P=0.039). Conclusion: The number of CD4⁺T, CD8⁺T, B, and NK cells significantly decreased in peripheral blood of SSc patients who had used immunosuppressive drugs, some lymphocyte subsets might be related with Raynaud’s phenomenon and fingertip ulcer, and reflected the disease activity by negatively correlated with ESR and CRP; the numbers of lymphocyte subsets in peripheral blood should be detected regularly in SSc patients who had taken immunosuppressive drugs.