This study expanded the "cell agglutination reaction" experiment in undergraduate cell biology teaching by integrating a sugar inhibition component. Lectins bind to specific sugars. In the traditional cell agglutination reaction, lectin is used to cause cells to aggregate via binding to sugars present on the cell surface. Here, various small sugars were added to red blood cell agglutination reactions. If the lectin binds to the added sugar that inhibits cellular aggregation. The degree of cellular aggregation was measured for each added sugar and controls, and hence used to assess the binding of the lectin to each sugar type. The experiment allows students to observe cell adhesion under the influence of lectin, deepening their understanding of glycosyl groups, lectin binding to sugar sites, inhibition of lectin binding, and the glycosyl composition of cell surfaces. The experimental approach cultivates students' problem-solving skills and enhances teaching effectiveness. By incorporating current real-world issues, students' interest in independent learning is increased.