This paper uses triangular fuzzy numbers to solve the weights of the evaluation indexes and then applies the improved TOPSIS method to evaluate the effectiveness of the construction of first-class undergraduate majors in colleges and universities. Empirical data were collected through questionnaires and materials related to the declaration of first-class major construction to verify the factors affecting the effectiveness of first-class undergraduate major construction and the comprehensive evaluation. The results show that four indicators, namely student learning outcomes, effective teaching practices, teacher-student interaction levels, and professional curriculum plans, explain 57.52% of the effectiveness of first-class undergraduate major construction. Among the ten universities, the relative closeness of the first-class undergraduate major construction effectiveness to the optimal solution of University D is 0.75221, and the major construction effectiveness is the most significant. The combination of students’ inputs and the effectiveness of first-class undergraduate major construction in universities under the background of deep learning can further enhance the depth of students’ learning for the major and promote the effectiveness of major construction.