Background The aim of this study was to explore the associations between the aspartate aminotransferase-to-alanine ami-notransferase ratio (AST/ALT) and coronary artery lesions (CALs) among patients with Kawasaki disease (KD).Methods Medical records of KD patients presenting to a single center between January 2019 and December 2020 were ret-rospectively collected and analyzed.Univariate,multivariable-adjusted analyses,subgroup analyses,restricted cubic spline test,and fitted curves were used to evaluate the associations between AST/ALT and CALs.Results A total of 831 patients were enrolled,of which 201 (24.2％) had CALs on admission and 21 (2.5％) developed CALs de novo after intravenous immunoglobulin (IVIG).Multivariable-adjusted analyses models revealed that a lower AST/ALT was associated with an increased risk of CALs on admission when AST/ALT was a continuous variable (P =0.007) and when it was a categorical variable (P for trend =0.004).Each unit increase in AST/ALT was associated with a 22％ lower risk of CALs on admission (odds ratio =0.78,95％ confidence interval 0.65-0.94).A negative linear relationship was noted between AST/ALT and the risk of CALs on admission in both observed and fitted models.However,such associations were not observed in AST/ALT and CALs de novo after IVIG.None of the variables significantly modified the association between AST/ALT and CALs on admission and CALs de novo after IVIG (P ＞ 0.05).Conclusion Our findings suggested that AST/ALT was a risk factor of CALs,but was not associated with progressive CALs.