The field of "technology and engineering" added in the primary school science curriculum standard is the consensus of science education in the world. It is both an opportunity and a challenge for front-line science teachers. This field provides students with the opportunity to synthesize all aspects of knowledge, and puts forward higher requirements for teachers to effectively guide and support students to complete the analysis and solution of practical problems and finally present products. Through case sharing, this paper helps front-line science teachers sort out the key links of "technology and engineering" in teaching practice, and teachers can develop normative and innovative "technology and engineering" teaching cases on this basis.