Objective To investigate the effects of splenectomy on peripheral immune cells including Th17 cells in patients with portal hypertension and to analyze the influence of splenectomy on their immune function. Methods Twenty- five portal hypertension patients treated with splenectomy in No. 180 Hospital of PLA from June 2012 to June 2014 were selected as observation group, and 25 healthy controls who underwent physical examination in the same period as control group. Flow cytometry was used to determine the percentages of CD3, CD4, and CD8 T lymphocytes, CD4 /CD8 ratio, and percentage of Th17 cells in the peripheral blood of portal hypertension patients ( 1 day before operation and at 7 days, 1 month, and 3 months after operation) and healthy controls. ELISA was used to evaluate the changes in serum interleukin- 6 ( IL- 6) , interleukin- 17 ( IL- 17) , and interleukin- 23 ( IL- 23) . Comparison between groups was made by one-way ANOVA and LSD- t test. Results Before splenectomy, the portal hypertension patients had significantly lower percentages of CD3, CD4, and CD8 T lymphocytes and CD4 /CD8 ratio ( P < 0. 01 for all) and significantly higher percentage of Th17 cells and levels of their associated inflammatory cytokines ( IL- 6, IL- 17, and IL- 23) ( P < 0. 01 for all) , as compared with the control group. At 7 days, 1month, and 3 months after operation, the percentages of CD3, CD4, and CD8 T cells and CD4 /CD8 ratio in portal hypertension patients first decreased and then increased, and these values were significantly lower at 7 days after operation than before operation ( P < 0. 01 for all) ; at3 months after operation, the patients showed no significant differences in the percentages of CD3, CD4, and CD8 T cells and CD4 /CD8 ratio compared with the control group ( P > 0. 05 for all) . At 7 days, 1 month, and 3 months after operation, the percentage of Th17 cells and levels of their associated inflammatory cytokines ( IL- 6, IL- 17, and IL- 23) in portal hypertension patients decreased gradually ( P <0. 05 for all) . Conclusion Th17 cells and their associated inflammatory cytokines ( IL- 6, IL- 17, and IL- 23) are reduced in portal hypertension patients treated with splenectomy, so their immune function can be improved.