As the expansion of higher vocational education hastens the massification of higher education, issues concerning the quality of teaching at higher vocational institutions have become increasingly apparent. This study addresses these concerns by integrating the PDCA (Plan-Do-Check-Act) cycle theory to develop a robust assessment system for evaluating teaching quality in higher vocational colleges. Utilizing a combination of hierarchical analysis and entropy weighting methods, the assessment system is enhanced both subjectively and objectively. By employing higher vocational colleges and universities labeled M1 to M6 as illustrative examples, we apply linear weighted summation to derive comprehensive evaluation scores from the tested teaching quality evaluation index system. The empirical results indicate that the cumulative variance contribution rate of the assessment indices reached 91.765%. In the quality assessment, M4 scored the highest with a composite score of 4.60, while M6 scored the lowest at 3.49. Comparative analysis across dimensions shows that the index scores for M6 were notably lower than those of other institutions, ranging between 3.20 and 3.80. Implementing the proposed teaching quality assurance system resulted in a substantial increase of 0.77 points in its comprehensive score. Thus, the assessment and assurance system developed in this study proves to be practically valuable, offering an effective means to enhance teaching quality and elevate the educational standards in higher vocational colleges.