I. Introduction
The novel coronavirus pneumonia has a great impact on normal school teaching. In order to effectively promote the teaching work during the epidemic period, the Ministry of education has put forward the requirement of “ceasing teaching, stopping classes and not stopping learning”, and the vocational colleges are actively responding to online teaching activities [1], The Ministry of education took the lead in organizing the development of online teaching solutions. Among the 22 online teaching platforms, 1291 national excellent online open courses and 401 national virtual experimental courses were opened for free. Among them, 18 professional categories were involved in junior college and higher vocational education. Higher vocational colleges in various regions have carried out online teaching orderly and achieved certain results. However, there are some problems in online teaching, such as the congestion of network platform, the unskilled online teaching of teachers and the low enthusiasm of students in online teaching [2],