The implementation of small-class seminar is an important measure to improve the quality of undergraduate education and build first-class universities in China. Obstacle factors of developing small-class seminar are analyzed by using the methods of literature research and expert consultation; the main causes of obstacle are determined based on establishing the interpretative structure model. In order to promote small-class seminar, it is particularly important for the government to change the development concept of undergraduate education and increase policy and financial support; furthermore, lead to the more concern and promote all-round reform in colleges and universities. On this basis, the relevant strategies are put forward and helpful for the government and colleges to ascertain breakthrough points to promote small-class seminar.