In this paper，teaching designs of a newly developed four 100% online teaching ( 100% student attendance， 100% serious attitude of learning，100% help to students with learning difficulties，100% answer rate of Wechat and Wechat group after class) and its implementation are introduced. Comparing the online teaching in 2020 with the offline teaching in 2019，it is found that the quality of online teaching based on this new online teaching design is equivalent to or greater than that of the offline teaching. However，the lack of face-to-face teacherstudent communication and student communication，the educating effect of online teaching is still unknown，and needs to be investigated in future.