"School's Out, But Class's On", i.e. "suspending classes without stopping learning", specifically refers to China's education and teaching activities during the postponement period during the COVID-19 pandemic prevention and control. This was an emergency measure to prevent and control the pandemic in the field of education in China, and it was also a continuation of school education in this special period. During the pandemic period, how school education should operate has become a topic of social concern. I herein discuss the origin and connotation of the concept of "School's Out, But Class's On", analyze the challenges of "School's Out, But Class's On" to school education, and then put forward measures for schools to respond to "School's Out, But Class's On" and explain the practical significance of "School's Out, But Class's On" for school education.