Large-scale online teaching has been widely adopted at various levels of education due to the outbreak of COVID-19. It is important for teachers to improve their online teaching pedagogies and competences. Based on the iterative learning and curriculum design theories, in this study, we build the Object-Content-Develop (OCD) online course development model. The model focuses on analyzing teaching problems of teachers’ online performances during the pandemic, formulating emergent course objectives, selecting precise curriculum content, and employing a “short, flat, and fast” method. We also develop a Massive Open Online Course (MOOC) named the Online Teaching in the Epidemic Period (OTEP) following the OCD model. The course has been implemented on two online platforms, i.e., the iCourse (Chinese University Massive Open Online Course) and the MOOC Alliance of the Colleges and Universities in Guangdong-Hong KongMacao Greater Bay Area (GBA-MOOC). More than 5,000 teachers, from higher education, vocational education, and K12, took this course. Results indicate that this OCD-model-based online course effectively enhances these teachers’ online teaching theories and practice. This research timely contributes to the online teaching professional development during the pandemic.