The purpose of this study is to investigate teachers' questioning and feedback in online college English classes. Teachers' questioning and feedback determine the success or failure of English teaching in online classes. The English teachers use questioning and feedback to promote students' language output and class interaction. However, nowadays, only some studies are focused on this field in China. Most studies of teachers' questioning and feedback were about traditional face-to-face classes. Therefore, this study intends to investigate teachers' questioning and feedback in online college English classes, expecting to give some hints to English teachers on using questioning and feedback. This research adopted mixed methods to study the use of college English teachers' questioning and feedback in online classes. The researcher observed seven online English classes on different online platforms at Jilin Agricultural Science and Technology University in the northeast of China to investigate how teachers use questioning and feedback, interviewed seven college English teachers to explore their opinions on the use of teachers' questioning and feedback, and finally surveyed 180 college students to probe their perceptions of EFL teachers' questioning and feedback in online classes. The findings show four leading online platforms used in online classes: QQ Group Classroom, Tencent WeMeet, DingTalk, and Xuexitong. Among them, the QQ Group Classroom was the leading platform used in online classes. Both teachers and students held a positive attitude toward using online platforms. They claimed the biggest benefits of online platforms were interactivity and accessibility. At the same time, the biggest challenge of using these online platforms was the network problem. Moreover, there were two types of teacher questioning on online platforms: display questioning and referential questioning. Generally, teachers used display questioning more frequently than referential questioning. There was a significant difference between display and referential questions on online platforms. Display questioning mainly occurred in the QQ Group Classroom and Xuexitong; referential questioning mainly occurred in DingTalk and the QQ Group Classroom. Additionally, there were five types of feedback on online platforms: positive feedback, clarification requests, elicitation, recasting, and repetition. Generally, teachers most frequently use positive feedback in these online classes. The findings also show that positive feedback, clarification requests, and elicitation had significant differences in the online platforms, while recast and repetition had no significant differences. The QQ Group Classroom helped create different types of questioning and feedback. The QQ Group Classroom and other platforms can improve online English teaching and interaction. Based on these findings, there were some suggestions for teachers: creating platform thinking, optimizing questioning and feedback skills, and establishing information literacy.