Teaching interaction is always one of the main problems in education, especially in MOOC education. In this paper, two persuasion methods of social psychology persuasion theory were used to research the influence of teachers’ answers on MOOC community discussion and teaching effect. Two courses in MOOC platform are selected as the research objects, and the discussion data in community of these course are analyzed to verify the influence of teachers’ answers on community discussion process. Through data analysis, it is found that teachers ‘answers in MOOC community discussion has a significant impact on students’ discussion activity and their knowledge construction stage.