Ideological and political course is a key course based on theoretical knowledge, which fosters souls and cultivates virtuous people. Based on the analysis from the perspective of epistemology, ideological and political courses in practical teaching have weak effect on knowledge realization. The construction of knowledge calls for stronger scientific rationality, the social pursuit of knowledge for bigger appeal, the complexity of knowledge for more precise targeting, and the practicality of knowledge for better effect. The "great ideological and political course" aims to enhance the scientific rationality in the integration and mutual construction of new knowledge and old knowledge, to generate appeal in the connection and sharing of space and time, to confirm the pertinence in the transformation and improvement of knowledge and belief, and to enhance practical effect in the interaction between theory and practice. The "great ideological and political course" in the new era stresses fostering virtue through education. It should realize the balance between supply and demand of knowledge, internalize the construction of conviction, practice from both macro and micro perspectives, and root in the value of practicality.