Objective To investigate the clinical significance of the changes of T lymphocyte immunity and cytokines in children with primary nephrotic syndrome (PNS). Methods A total of 30 children with PNS admitted to our hospital from June 2015 to March 2019 were selected as the research objects and divided into active group (13 cases) and remission group (17 cases) according to disease progression. Meanwhile, 30 healthy children were selected as the control group. The levels of CD3+, cytotoxic T cell (Tc), helper T cell (Th), Th/Tc and interleukin-6 (IL-6) in the three groups were compared. Results There was no statistically significant difference in CD3+level among the three groups (P>0.05).Th and Th/Tc levels in the active group and the remission group were lower than those in the control group, and the differences were statistically significant (P<0.05). Tc and IL-6 levels in the active group and the remission group were higher than those in the control group, and the differences were statistically significant (P<0.05). Th and Th/Tc levels in the active group were lower than those in the remission group, and the differences were statistically significant (P<0.05). Tc and IL-6 levels in the active group were higher than those in the remission group, and the differences were statistically significant (P<0.05). IL-6 was positively correlated with Tc (r=0.91, P<0.01), negatively correlated with Th(r=-0.92, P<0.05) and negatively correlated with Th/TC (r=-0.90, P<0.05). Conclusion There are changes in T lymphocyte subsets and cytokines in children with PNS, which may play a role in the pathogenesis of PNS.