Abstract: Undergraduates majoring in chemical engineering should master the "scale-up criteria" research method of chemical reactors,and be familiar with the phenomena and laws in the process of reactor scale-up. In this paper,the scale-up principle of the tank stirred reactor was investigated by step-by-step scale-up experiment. The residence time distribution of the reactor was deter-mined by the tracer pulse method to determine the flow characteristics of the reactor,and the flow model parameters of the reactor were obtained. The experiment requires the students to compare the flow characteristics and conversion rate of the reactor obtained by com-paring the stirring speeds of different scale-up criteria,and summarize the advantages and disadvantages of different scale-up crite-ria,which provides a basis for the design and scale-up of the reactor. Through this experiment,the students' engineering awareness, hands-on ability and teamwork ability have been effectively improved,and the students' experimental design ability and result analy-sis ability have been improved,and the teaching purpose of engineering experiments has been realized.