By explaining the knowledge points of "machining error, machining accuracy and tolerance", the ideological and political elements are accurately integrated and gradually sublimated. To cite the engineering example of China's high-speed rail, the fact that "missing a tiny bit is a thousand miles away", and a seemingly small error can also lead to unimaginable consequences is proved. Thus, we should cultivate the students' rigorous and serious attitudes towards work and the spirit of craftsmanship, to bring forth new ideas and realize independent innovation.