To compare the outcomes of totally percutaneous in situ microneedle puncture for left subclavian artery (LSA) fenestration (ISMF) and chimney technique in type B aortic dissection (TBAD) during thoracic endovascular aortic repair (TEVAR). Data on patients who underwent either chimney-TEVAR (n = 89) or ISMF-TEVAR (n = 113) from October 2018 to April 2022 were analyzed retrospectively. The primary outcomes were mortality and major complications at 30 days and during follow-up. The technical success rate was 84.3% in the chimney group and 93.8% in the ISMF group (p = 0.027). The incidence of immediate endoleakage was significantly higher in the chimney than ISMF group (15.7% vs 6.2%, respectively; p = 0.027). The 1- and 3-year survival rates in the chimney and ISMF groups were 98.9% ± 1.1% vs 98.1% ± 0.9% and 86.5% ± 6.3% vs 92.6% ± 4.1%, respectively (log-rank p = 0.715). The 3-year rate of cumulative freedom from branch occlusion in the chimney and ISMF group was 95.4% ± 2.3% vs 100%, respectively (log-rank p = 0.023). Both ISMF-TEVAR and chimney-TEVAR achieved satisfactory short- and mid-term outcomes for the preservation of the LSA in patients with TBAD. ISMF-TEVAR appears to offer better clinical outcomes with higher patency and lower reintervention rates. However, ISMF-TEVAR had longer operation times with higher procedure expenses. When LSA revascularization is required during TEVAR, in situ, fenestration, and chimney techniques are all safe and effective methods; in situ, fenestration-TEVAR appears to offer better clinical outcomes, but takes longer and is more complicated. LSA revascularization during TEVAR reduces post-operative complication rates. Both in situ ISMF-TEVAR and chimney-TEVAR are safe and effective techniques for the preservation of the LSA during TEVAR. The chimney technique is associated with a higher incidence of endoleakage and branch occlusion, but ISMF-TEVAR is a more complicated and expensive technique.