Abstract: Objective To investigate the effect of percutaneous transhepatic insertion of biliary stent (PTIBS) on the immunological indexes of patients with malignant biliary obstruction. Methods From February 2016 to June 2018, 124 patients with malignant biliary obstruction admitted to Qinhuangdao First Hospital were randomly divided into PTIBS group and percutaneous transhepatic cholangial drainage (PTCD) group, 62 cases in each group. The clinical efficacy and immunological indexes between the two groups were compared. Results The total effective rate of the PTIBS group was significantly higher than that of the PTCD group (95.16% vs.72.58%, P<0.05). There was no significant difference in CD4⁺, CD8⁺, CD4⁺/CD8⁺ between the two groups before treatment (P<0.05). After treatment, CD4⁺, CD8⁺ and CD4⁺/CD8⁺ in the PTIBS group were significantly higher than those in the PTCD group (P<0.05). There was no significant difference in the levels of IgA, IgM and IgG between the two groups before treatment (P>0.05). After treatment, the levels of IgA, IgM and IgG in the PTIBS group were significantly lower than those in the PTCD group (P<0.05). Conclusions In the treatment of malignant biliary obstruction, PTIBS is superior to PTCD group in therapeutic effect and improvement of cellular immune function, which has a good clinical application value.