The HyFlex course has been widely adopted in higher education settings. However, there is a paucity of empirical studies examining students' acceptance of large-scale HyFlex courses, as well as factors influencing their acceptance. To fill this research gap, the present study investigated students' acceptance of a large-scale HyFlex course and the variations in their acceptance according to different participation modes (ie, on-site, synchronously online and mixed attendance), based on a total of 160 valid samples from a large-scale HyFlex course at a normal university in central China during the fall semester of 2022. The results indicated that students' overall HyFlex course acceptance was generally high, and the students who alternately engaged in on-site and synchronously online learning had the highest level of acceptance. Furthermore, this study employed structural equation modelling to validate a model integrating the unified theory of acceptance and use of technology with connected classroom climate (CCC). The findings showed that performance expectancy (PE), effort expectancy, facilitating conditions and CCC directly influenced students' acceptance, with performance expectancy having the strongest direct effect. However, social influence only had an indirect effect on students' acceptance, while CCC had both direct and indirect effects. This study carries substantial theoretical and practical implications, enhancing our understanding of students' acceptance of the HyFlex learning approach.