Background: HE is a common and dangerous complication after TIPS. The relationship between IL-6 levels and overt HE (OHE) after TIPS is rarely reported.We aimed to explore the relationship between the preoperative serum IL-6 levels and OHE risk after TIPS, and to evaluate its value in predicting the OHE risk. Methods: This prospective cohort study included 125 participants with cirrhosis who received TIPS. Logistics regression analyses were performed to explore the relationship between IL-6 and OHE risk, and the receiver operating characteristic analysis was used to compare the predictive power of IL-6 and other indexes. Results: Among 125 participants, 44 (35.2%) participants developed OHE after TIPS. Logistics regression showed preoperative IL-6 was associated with a higher OHE risk after TIPS in different models (all p < 0.05). Participants with IL-6 > 10.5 pg/mL had a higher cumulative incidence of OHE after TIPS than those with IL-6 ≤ 10.5 pg/mL (log-rank = 0.0124). The predictive power of IL-6 (AUC = 0.83) for the OHE risk after TIPS was higher than that of other indexes. Age (RR = 1.069, p = 0.002) and IL-6 (RR = 1.154, p < 0.001) were independent risk factors for OHE after TIPS. IL-6 was also a risk factor for the occurrence of coma in patients with OHE (RR = 1.051, p = 0.019). Conclusion: Preoperative serum IL-6 levels are closely related to the occurrence of OHE in patients with cirrhosis after TIPS. Patients with cirrhosis with high serum IL-6 levels following TIPS were at a higher risk of developing severe HE.