Thoracic aortic endovascular repair (TEVAR) is the primary treatment for Stanford type B aortic dissection (type B AD). However, patients often encounter significant difficulties post-TEVAR that endanger their safety when transitioning from hospital- to home-based care. Moreover, information on the ideal transitional care for patients with type B AD post-TEVAR is scarce in China. This single-masked randomized clinical trial aimed to assess the effectiveness of the Assess, Advise, Agree, Assist, and Arrange (5As) model-based transitional care in improving discharge preparation level and transitional care quality post-TEVAR among patients with type B AD in China. This study was conducted at a hospital in China between January 2021 and October 2021. Patients with type B AD were randomly divided into intervention and control groups. Participants in the intervention group received the 5As model-based transitional nursing care. The 5As model is an evidence-based intervention strategy comprising: (1) Assess: assessing the preoperative cardiovascular risk behavior of patients with AD. (2) Advise: making suggestions according to the risk behaviors of the patients. (3) Agree: reaching a consensus on goals and action plans by making decisions with the patients and their families. (4) Assist: assisting patients in solving obstacles to implementing health plans. (5) Arrange: arranging follow-up visits according to the actual situation of the patients and guiding them in adhering to a schedule. The control group received the usual nursing care for the same duration and number of follow-up visits. A trained research nurse collected all the baseline data of the patients on admission, assessed discharge readiness level (using the Readiness for Hospital Discharge Scale) on the day of discharge, and collected transitional quality of care (by the Care Transition Measure-15) data on day 30 after discharge. Overall, 72 patients with type B AD were recruited. Discharge readiness level and transitional care quality in the intervention group were significantly superior to those in the control group. This study showed that the 5As model-based transitional care program can effectively promote discharge readiness and transitional care quality of patients with type B AD post-TEVAR. The Chinese Clinical Trial Registry Center: ChiCTR2200060797 (https://www.chictr.org.cn/showproj.html?proj=167403).