This study explores the construction path of the “big ideological and political courses” in universities from the perspective of intersubjectivity. To go beyond the conceptual discussions, this study developed the “Intersubjectivity Co-construction Index” (ICI) and utilized multi-source data to measure how teacher-student dialogue, students’ autonomy, course integration, social practice linkage, and digital feedback jointly shape educational outcomes. The empirical design included 1,260 valid student questionnaires, 96 teacher questionnaires, 21 courses, 36 practical projects, 12 weeks of platform behavior records, and 57 semi-structured interviews. The measurement results showed that this index system has good reliability and validity. The Cronbach’s alpha value ranged from 0.84 to 0.89, the composite reliability (CR) ranged from 0.87 to 0.91, and the average variance extracted (AVE) ranged from 0.58 to 0.66. In the baseline dimension, the average score of course integration was the highest, at 3.61, while the score of social practice linkage was the lowest, at 3.17. This indicates that the current construction of “big ideological and political courses” is more prominent in course organization than in the transformation based on practice. Path analysis further demonstrated that personalized teaching significantly enhanced students’ participation, with a standardized coefficient of 0.46, and directly promoted value internalization, with a coefficient of 0.31. Students’ participation also promoted value internalization, with a coefficient of 0.38, while the connection of social practice activities had the most significant direct impact on value internalization, with a coefficient of 0.42. The 12-week intervention confirmed the effectiveness of the optimized model. Compared to the control group, the experimental group had a net improvement of 0.31 in student participation, 0.28 in value internalization, 0.36 in the quality of practical reflection, and 0.33 in the depth of digital discussion. Heterogeneity analysis further indicated that freshmen benefited more from teacher-student dialogue, senior students responded more strongly to social practice activities, science and engineering students were more sensitive to professional case integration, and humanities students relied more on dialogue and reflection. This study provides a measurable framework, an empirical testing strategy, and an optimized construction path for the GIPC reform.
