Triglyceride-glucose (TyG) index is considered a simple and feasible indicator of insulin resistance (IR). This study aims to delve into the association and interaction of TyG index on the risk of prehypertension in Chinese adults. A community based cross-sectional survey conducted in Chinese population. Eligible participants were recruited, and questionnaire survey, anthropometric tests, and blood samples collection were performed. TyG index was obtained as ln [fasting TG(mg/dl) × FPG(mg/dl)/2]. Logistic regression model and the area under the receiver-operating characteristics (ROC) curves (AUC) were analyzed. Interaction analysis was conducted by calculating relative excess risk for interaction (RERI), attributable proportion for interaction (AP) as well as synergy index (SI). A total of 3115 recruited participants (1307 males and 1808 females) were aged 60.82 years on average. The prevalence of prehypertension reached 36.4% on the whole, 37.6% in male and 35.5% in female, respectively. The results of multivariable logistic regression model suggested that the adjusted OR for prehypertension was upregulated across TyG index quartiles, up to 2.06 (95% CI:1.53–2.77) for quartiles 4 versus quartiles 1. Furthermore, TyG index outperformed FPG (Z = 2.15, p = 0.032) and TG (Z = 6.10, p < 0.001) in discriminating prehypertension risk. Besides, TyG index with abdominal obesity (RERI:1.53, 95% CI:0.39–2.67; AP: 0.37, 95% CI: 0.16–0.59; SI:1.96, 95% CI:1.15–3.34) displayed a noticeable interaction on risk of prehypertension. Our study indicated that a higher TyG index rose the risk of prehypertension independently and synergistically with abdominal obesity in Chinese adults. Furthermore, it exhibited a higher predictability compared with conventional indices.