The 2020 edition of College English Teaching Guide states that college English should give full play to the important role of modern information technology in English teaching and vigorously promote the intensive integration of modern information technology with curriculum teaching. Based on the teaching practice of medical English, this paper takes the microlecture "The mystery of diabetes" as an example, which was awarded the first prize in the Fifth China Foreign Language Microlecture Competition organized by the Higher Education Academy in 2019 to analyze the concept and connotations of microlectures and to elucidate the designing principles of topic selection, script composition and production of medical English microlectures, thereby proposing the ideas of application-orientation, centeredness on students' needs, form and function integration, practicality-prioritization and putting forward some thoughts on the application of medical English microlectures in teaching practice. An excellent microlecture should be effectively utilized and fed back to teaching. The "four in one" microlecture teaching concept helps to improve the teaching effect of medical English microlectures.