We summarized the inquiry teaching experience before and presented a new teaching mode based on a three phase teaching method. The first phase was the natural teaching phase, in which teachers proposed simple group projects to training students’ study interests. The second phase was the unnatural teaching phase. In this phase, teachers increased the difficulty of group projects to enhance students’ theories. Teachers also guided students to solve problems in the projects to broaden students’ knowledge. The third phase is scientific natural phase. Students’ learning initiative and innovative ability were promoted. They can complete projects by themselves. The results show that the three phase teaching method can broaden students’ knowledge, enhance students’ learning initiative and abilities of self study, innovation, communication and teamwork, and promote students’ engineering quality.