Based on the online course of Medical Imaging, the online and offline mixed teaching mode is an important reform against the traditional teaching mode. Combining the teaching reform experience of Chongqing Medical University, this paper introduces the resource construction of the online teaching platform of Medical Imaging, the construction of the online and offline mixed teaching mode (including the overall reconstruction design of the online and offline teaching content, and the organic integration of the online and offline teaching content before, during and after class), the details of teaching implementation (taking ischemic cerebral infarction as an example), the teaching efficiency, the existing problems and related improvement measures. The preliminary practice shows that it has great significance in enhancing the teaching quality since it can break through time and space constraints, expand teaching space, effectively stimulate students' learning autonomy, enhance their practical skills, increase the communication and interaction between teachers and students, and improve the teaching effect.