Of the student autonomic learning-oriented and teacher guidance-supplemented teaching mode, the discussion teaching method was applied in air conditioning engineering teaching. A series of studies on selecting items, teaching form, evaluation and teachers’ assessment were proposed. The key of a successful classroom discussion lies in items selecting, student’s active participation and teacher’s instruction. The result of teaching practice shows that discussion teaching method can develop student’s comprehensive applied ability and innovative ability, so as to enhance the teaching quality of air conditioning engineering effectively.