Background. Triglyceride/high-density lipoprotein cholesterol (TG/HDL-c) ratio varies with vascular and other metabolic diseases. However, its role in acute type B aortic dissection is not well understood. In the current study, we evaluated the relationship between TG/HDL-c ratio and in-hospital mortality in type B aortic dissection. Methods. We performed a retrospective analysis of consecutive patients between January 2015 and December 2018, by targeting dependent (TG/HDL-c ratio) and independent (inhospital mortality) variables. TG/HDL-c ratio was determined as a division of TG levels by HDL-c levels. Results. Of 523 patients in the study, we found a mean age of 55:00 ± 11:74 years, 15.68% of them being female. A fully-adjusted model revealed a positive relationship between TG/HDL-c ratio and in-hospital mortality in acute type B aortic dissection after adjusting confounders (OR = 2:08, 95% CI 1.32 to 3.27). This relationship was also nonlinear, with a point of 2.05. OR values (and confidence intervals) for the right (>2.05) and left (≤2.05) sides of the inflection point were 1.0 (0.580-1.26, P = 0:983) and 3.17 (1.54-6.57, P = 0:001), respectively. Conclusions. The TG/HDL-c ratio and in-hospital mortality in type B AAD have a nonlinear relationship among Chinese population. This ratio increased in-hospital mortality when it is less than 2.05.