A series of improvements were made by redesigning the classic organic experiment"Preparation of n-bromobutane".A combination of experimental conditions was designed for different dosages,reaction times,and addition orders.Fifteen students were selected to join dynamic grouping.The optimal experimental conditions were obtained through comprehensive discussion of experimental data,and the abnormal experimental results were explained.At the same time,rapid identification was carried out using NMR and GC-MS.The students in the dynamic group showed a significant improvement in the experimental and instrument operations.Finally,students were guided to think creatively,which enhances their ability to ask questions,solve problems,and design new experiments,and achieves good teaching results.