At the beginning of 2020, due to the global outbreak of COVID-19, many face to face courses have been forced to switch to online courses, which led to increased focus on online teaching methods. Based on the experience of researcher in the Czech Republic and relevant literature, this study emphasizes the importance of learners’ ability to communi-cate, interact, and collaborate in online courses, therefore the researcher choose online communicative language teaching tasks suitable for beginners, based on task types pro-posed by previous studies and other researchers who used communicative tasks in their researches, including Role-Play, Information Gap, Guess What I say(do) and Jigsaw. Additionally, online synchronous courses were designed according to the three-stage teaching design framework proposed by Lin and Huang (2016).

　　In this study, three teaching experiments were conducted to observe learners’ behav-ioral responses before and after participating in online tasks. These responses were rec-orded in teaching journals and video checklists, and the revisions of activities were made based on reflective practices after each teaching session. Additionally, the research also conducted a questionnaire survey and interview method to analyze online course and the communicative language teaching tasks from learners’ perspective. It revealed learners' views and attitudes towards online course and communicative language teaching tasks. The research results show that all four communicative language teaching tasks can be ap-plied to online synchronous teaching, among which Role-Play and Guess What I say(do) are the most popular among learners. Finally, the conclusion of this study also puts for-ward teaching suggestions for future research.