Affected by the epidemic, most of the teaching activities have been converted to online teaching methods, exploring informatized teaching methods and ensuring the quality of online teaching is a common challenge faced by teachers and students. The characteristics of SPOC, Rain Classroom, Dingding Live and other teaching modes are analyzed, and the integrated online smart teaching mode of "SPOC + Rain Classroom + Dingding" is discussed from the aspects of teaching resource preparation, teaching activity design, and evaluation system establishment. The preliminary practice of teaching professional courses in engineering has achieved good results, which can provide a reference for online teaching of professional courses in colleges and universities.