The development of internet technology has gradually changed the way of language learning. Online synchronous lessons further promote learning without geographical restrictions. Due to its difference from classroom teaching, teachers face many issues: operation of teaching platform, change in teacher–student interaction, and change in teaching context. Therefore, training for online synchronous teaching is necessary. This research observes both in-class courses of the “2018 Web-Based Chinese Language Teaching Practice” of National Taiwan Normal University, and online teaching collaboration with “Pre-Advanced Chinese Course” at the University of Virginia. The online teaching practical internship was over the course of 14 weeks in the Fall Semester of 2018. During this training: theoretical courses, practical teaching, reflection and discussion are repeated. The questionnaire survey method was used to collect the reflections of 37 pre-service teachers. The performance of pre-service teachers’ self-growth, action strategies, and collaborative learning were then analyzed. When the course was concluded, we interviewed six graduates who became online teachers, analyzed their feedback, and discussed what benefits had derived from the training for their online teaching needs. In this study, pre-service teachers learn foundational teaching theories, engage in reflective discussion, and participate in peer-to-peer collaborative learning. Mutual assistance and support are emphasized in group work. What kind of progress can result through this training course? What difficulties are encountered by these participants in the training? How do we come up with strategic solution? These are the questions we are investigating in this study. We wanted to explore the deficiencies in the training and various areas that requires further reinforcement and strengthening. Comprehensive questionnaires and reflections from pre-service teachers, and interviews with current teachers after training, put forth the items that need to be explored in the future training online. This is to serve as reference for planning training courses of the same nature.