This paper makes a practical exploration of the online teaching method of the postgraduate professional course "Building Energy Conservation". Through the questionnaire survey of graduate students, the advantages and disadvantages of online teaching are analyzed, and corresponding countermeasures are taken. According to the characteristics of small-class teaching, Tencent class can be selected for course recording and playback, and combined with the QQ group sharing teaching form with better screen function and smooth operation; Use live online video teaching and interspersed with irregular questions to deal with the poor state of online teaching students; To mobilize students study enthusiasm, stimulate the learning motivation and professional interests of STU teaching mode, pay attention to the cultivation of the students" ability of autonomous learning, from the perspective of professional interests, will be boring static knowledge by using simulation software such as digital information means into dynamic interest in learning, curriculum knowledge into each student"s research direction, and complement each other in the team cooperation, from the view of the sustainable development of building energy efficiency and develop the students" scientific thinking, improve students" innovation consciousness.