Mucosa-associated lymphoid tissue 1 (MALT1) regulates inflammation and T helper (Th) cell differentiation, which may participate in the progression of Stanford type A aortic dissection (TAAD). This study intended to assess the association of MALT1 expression with prognosis in TAAD patients. In this prospective study, MALT1 expression was measured by reverse transcription-quantitative polymerase chain reaction assay from peripheral blood samples in 100 TAAD patients and 100 non-AD controls (non-AD patients with chest pain) before treatment. Besides, Th1, Th2, and Th17 cells of TAAD patients before treatment were measured by flow cytometry assay, and their 30-day mortality was recorded. MALT1 expression was ascended in TAAD patients versus non-AD controls (P<0.001). In TAAD patients, elevated MALT1 expression was linked with hypertension complication (P=0.009), increased systolic blood pressure (r=0.291, P=0.003), C-reactive protein (CRP) (r=0.286, P=0.004), and D-dimer (r=0.359, P<0.001). Additionally, MALT1 expression was positively correlated with Th1 cells (r=0.312, P=0.002) and Th17 cells (r=0.397, P<0.001), but not linked with Th2 cells (r=-0.166, P=0.098). Notably, the 30-day mortality of TAAD patients was 28.0%. MALT1 expression [odds ratio (OR)=1.936, P=0.004], CRP (OR=1.108, P=0.002), D-dimer (OR=1.094, P=0.003), and surgery timing (emergency versus selective) (OR=8.721, P=0.024) independently predicted increased risk of death within 30 days in TAAD patients. Furthermore, the combination of the abovementioned independent factors had an excellent ability in predicting 30-day mortality with the area under curve of 0.949 (95% confidence interval: 0.909-0.989). MALT1 A c c e p t e d M a n u s c r i p t 3 expression relates to increased Th1 cells, Th17 cells, and 30-day mortality risk in TAAD patients.