Objective To compare the early clinical outcomes of the Castor single-branch stent graft system and the chimney stent technique in thoracic endovascular aortic repair (TEVAR) for Stanford type B aortic dissection (TBAD) involving the left subclavian artery (LSA).Methods A total of 83 patients with TBAD involving the LSA, admitted between May 2021 and May 2024, were included. Patients were divided according to surgical technique into the control group (n = 42, chimney stent technique) and the observation group (n = 41, Castor single-branch stent graft). Perioperative indicators, LSA patency, aortic remodeling outcomes, and complication rates were compared between the two groups.Results The operation time and fluoroscopy time in the observation group were significantly longer than those in the control group (P < 0.05). No statistically significant difference was found in the length of hospital stay between the two groups (P > 0.05). The LSA patency rate was 100.00% in both groups during hospitalization, and no significant difference was observed between the two groups at the 1-year follow-up (P > 0.05). Comparison of true lumen and false lumen diameters between the two groups revealed: (1) significant differences at different time points (P < 0.05); (2) significant differences between the observation and control groups (P < 0.05), with the observation group exhibiting a larger postoperative true lumen diameter and a smaller false lumen diameter, indicating superior endovascular repair outcomes; (3) significant differences in the trends of diameter changes between the two groups (P < 0.05). The false lumen thrombosis rate was significantly higher in the observation group than in the control group (P < 0.05). The incidence of type I endoleak was significantly lower in the observation group than in the control group (P < 0.05). No statistically significant differences were found in the rates of stroke or spinal cord ischemia between the two groups (P > 0.05).Conclusion The Castor single-branch stent graft, while prolonging operation and fluoroscopy time, significantly reduces the risk of type I endoleak, promotes false lumen thrombosis and favorable aortic remodeling, and maintains long-term LSA patency. It demonstrates favorable early safety and efficacy.