A correct understanding of the formation mechanism of rainbow can help students form a correct cognition of atmospheric optical phenomena. In this paper, a rainbow reproduction device is designed for students to build by themselves, and the influencing factors of rainbow reproduction are analyzed based on the device. It is found that it is easier to observe clear and bright rainbow when the droplet group with uniform distribution and large density is irradiated by the light source with good parallelism. Finally, the polarization characteristics of rainbow are demonstrated.